There remain several intractable challenges for chemotherapy in glioma treatment,including the blood-brain barrier(BBB),blood-brain tumor barrier(BBTB),and tumor heterogeneity caused by cancer stem cells(CSCs),which a...There remain several intractable challenges for chemotherapy in glioma treatment,including the blood-brain barrier(BBB),blood-brain tumor barrier(BBTB),and tumor heterogeneity caused by cancer stem cells(CSCs),which are resistant to conventional chemotherapy.Here,we established a nano strategy to kill glioma cells and CSCs,combining carfilzomib and bis(diethyldithiocarbamate)copper.The synergistic drug combination disturbed cell protein metabolism at different stages and induced apoptosis and cuproptosis.The Y-shaped targeting ligand pHA-VAP-modified nanodiscs were designed to help the chemotherapeutic agents cross the BBB/BBTB and finally accumulate in tumor site.This all-stage targeting and all-stage treatment nanomedicine significantly prolonged the survival in glioma-bearing mice and might inspire the rational design of advanced drug delivery platforms.展开更多
In this paper,a multi-stage leaching process for the weathered crust elution-deposited rare earth ore was proposed using MgSO_(4)as a leaching agent.The results indicate that with increasing the concentration of MgSO_...In this paper,a multi-stage leaching process for the weathered crust elution-deposited rare earth ore was proposed using MgSO_(4)as a leaching agent.The results indicate that with increasing the concentration of MgSO_(4)from 0.5 wt%-1.0 wt%to 2.0 wt%-4.0 wt%,the peak concentrations of rare earths increase from 1.87 to 3.59 to 5.49-10.21 g/L,and the collection periods of leach solution are sho rtened from 0.85 to 1.54 to 0.31-0.47(liquid-to-ore ratio).When the rare earth ore is leached with leaching agent solution with high initial pH(3.0-5.0),the rare earths and aluminum are predominantly leached by Mg^(2+)instead of H+.However,H+participate in the leaching process of rare earths and aluminum at lower initial pH(1.5-3.0)of the leaching agent solution.Especially,when the initial pH of leaching agent solution is 2.0,a large amount of aluminum is leached when the liquid-to-ore ratio is greater than 1.2.Based on the above insights,increasing the initial pH(3.0-5.0)of leaching agent solution in the injection stage using high-concentration MgSO_(4)(>1.0 wt%)can increase the peak concentration of rare earths in the leach solution and shorten the collection period.However,in the injection stage using low MgSO_(4)concentration(<1.0 wt%),an initial pH of leaching agent solution of 2.0 is selected to reduce the leaching amount of aluminum and the consumption of MgSO_(4).Comparing to the Leaching process using constant MgSO_(4)concentration(2.0 wt%,initial pH of 5.0),the leaching efficiency of rare earths using a multi-stage leaching process is approximately equal(about 94.6%)under optimal conditions.The leaching amount of aluminum is reduced by 16.9%.The consumption of MgSO_(4)is reduced by 67.1%.展开更多
In order to clarify the solvent extraction and separation behaviors of rare earths and impurity of Al during the extraction and enrichment of low-concentration leach solution of ion-adsorption rare earth ore,the extra...In order to clarify the solvent extraction and separation behaviors of rare earths and impurity of Al during the extraction and enrichment of low-concentration leach solution of ion-adsorption rare earth ore,the extraction mechanism and separation behaviors of Nd^(3+)and Al^(3+)in the Nd_(2)(SO_(4))_(3)-AI_(2)(SO_(4))_(3) mixed solution using P507 were studied in this work.The extraction of Nd^(3+)and Al^(3+)follows the cation exchange mechanism.With the increase of the equilibrium pH,β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution using P507 is always higher than that in the extraction of single Nd_(2)(SO_(4))_(3) and Al_(2)(SO_(4))_(3) solutions.It can be attributed to the fact that the extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),and Al^(3+)is more prone to be hydrolyzed at lower pH.β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution decreases gradually with the increase of mixing time within the equilibrium pH range of 1.5-1.9.The extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),but the stability of Al^(3+)-Ioaded organic phase is better than that of Nd^(3+)-loaded organic phase,thus Nd^(3+)in the Nd^(3+)-loaded organic phase is gradually replaced by Al^(3+)in the aqueous phase with the increase of mixing time.展开更多
The objective of this study is to investigate the effects of the Coulomb dry friction model versus the modified Coulomb friction model on the dynamic behavior of the slider-crank mechanism with a revolute clearance jo...The objective of this study is to investigate the effects of the Coulomb dry friction model versus the modified Coulomb friction model on the dynamic behavior of the slider-crank mechanism with a revolute clearance joint. The normal and tangential forces acting on the contact points between the journal and the bearing are described by using a Hertzian-based contact force model and the Coulomb friction models, respectively.The dynamic equations of the mechanism are derived based on the Lagrange equations of the first kind and the Baumgarte stabilization method. The frictional force is solved via the linear complementarity problem(LCP) algorithm and the trial-and-error algorithm.Finally, three numerical examples are given to show the influence of the two Coulomb friction models on the dynamic behavior of the mechanism. Numerical results show that due to the stick friction, the slider-crank mechanism may exhibit stick-slip motion and can balance at some special positions, while the mechanism with ideal joints cannot.展开更多
The non-smooth dynamic model of an unmanned bicycle is established to study the contact-separate and stick-slip non-smooth phenomena between wheels and the ground.According to the Carvallo-Whipple configuration,the un...The non-smooth dynamic model of an unmanned bicycle is established to study the contact-separate and stick-slip non-smooth phenomena between wheels and the ground.According to the Carvallo-Whipple configuration,the unmanned bicycle is reduced to four rigid bodies,namely,rear wheel,rear frame,front fork,and front wheel,which are connected by perfect revolute joints.The interaction between each wheel and the ground is simplified as the normal contact force and the friction force at the contact point,and these forces are described by the Hunt-Crossley contact force model and the Lu Gre friction force model,respectively.According to the characteristics of flat and curved pavements,calculation methods for contact forces and their generalized forces are presented.The dynamics of the system is modeled by the Lagrange equations of the first kind,a numerical solution algorithm of the dynamic equations is presented,and the Baumgarte stabilization method is used to restrict the drift of the constraints.The correctness of the dynamic model and the numerical algorithm is verified in comparison with the previous studies.The feasibility of the proposed model is demonstrated by simulations under different motion states.展开更多
Utilization of carbon-based materials is crucial for mitigating CO_(2) emissions.However,practical materials for CO_(2) capture remain challenging due to limitations in adsorption capacity and rate.Inspired by the uni...Utilization of carbon-based materials is crucial for mitigating CO_(2) emissions.However,practical materials for CO_(2) capture remain challenging due to limitations in adsorption capacity and rate.Inspired by the unique structural features of biomass materials,high-performance hierarchical porous carbon was prepared using vascular plants.The ordered arrangement structure effectively improved the adsorption capacity and rate of the material by optimizing the pore structure.Potassium hydroxide(KOH)was used as an activator to synthesize microporous carbon with an ordered hierarchical structure.The properties of hierarchical porous carbon were characterized.The experimental results indicate that porous carbon prepared from loofah complex has excellent CO_(2) adsorption capacity.The highest adsorption capacity is 4.09 mmol/g when the activation temperature is 700℃.The selectivity(15/85)for the binary gas mixture CO_(2)/N_(2) was 20,and the recoverability was good after 10 cycles.The hierarchical porous carbon derived from loofah showed excellent adsorption performance and has potential in various applications.展开更多
Integrating a battery energy storage system(ESS)with a large wind farm can smooth the intermittent power obtained from the wind farm,but the smoothing function will not be achieved if multiple ESSs are used to smooth ...Integrating a battery energy storage system(ESS)with a large wind farm can smooth the intermittent power obtained from the wind farm,but the smoothing function will not be achieved if multiple ESSs are used to smooth the fluctuations in individual wind power plants in a distributed pattern.Therefore,this study focuses on the development of a control strategy to optimize the use of multiple ESSs to accelerate the adoption of wind energy resources.This paper proposes a quasi-automated generation control(QAGC)strategy to coordinate multiple ESSs,which responds to the grid dispatch demand rather than smoothing out the intermittent power from individual wind farms.The aims of QAGC are to ensure that multiple ESSs provide a service that is as balanced as possible,so more wind power systems at various scales can be accepted by the grid,as well maximizing the low-carbon benefits of ESSs.The effectiveness of QAGC is demonstrated by using data from an actual gigawatt scale cluster of wind plants.展开更多
This paper presents a high-performance MEMS accelerometer with a DC/AC electrostatic stiffness tuning capability based on double-sided parallel plates(DSPPs).DC and AC electrostatic tuning enable the adjustment of the...This paper presents a high-performance MEMS accelerometer with a DC/AC electrostatic stiffness tuning capability based on double-sided parallel plates(DSPPs).DC and AC electrostatic tuning enable the adjustment of the effective stiffness and the calibration of the geometric offset of the proof mass,respectively.A dynamical model of the proposed accelerometer was developed considering both DC/AC electrostatic tuning and the temperature effect.Based on the dynamical model,a self-centering closed loop is proposed for pulling the reference position of the forceto-rebalance(FTR)to the geometric center of DSPP.The self-centering accelerometer operates at the optimal reference position by eliminating the temperature drift of the readout circuit and nulling the net electrostatic tuning forces.The stiffness closed-loop is also incorporated to prevent the pull-in instability of the tuned low-stiffness accelerometer under a dramatic temperature variation.Real-time adjustments of the reference position and the DC tuning voltage are utilized to compensate for the residue temperature drift of the proposed accelerometer.As a result,a novel controlling approach composed of a self-centering closed loop,stiffness-closed loop,and temperature drift compensation is achieved for the accelerometer,realizing a temperature drift coefficient(TDC)of approximately 7μg/℃ and an Allan bias instability of less than 1μg.展开更多
This paper reports an approach of in-operation temperature bias drift compensation based on phase-based calibration for a stiffness-tunable MEMS accelerometer with double-sided parallel plate(DSPP)capacitors.The tempe...This paper reports an approach of in-operation temperature bias drift compensation based on phase-based calibration for a stiffness-tunable MEMS accelerometer with double-sided parallel plate(DSPP)capacitors.The temperature drifts of the components of the accelerometer are characterized,and analytical models are built on the basis of the measured drift results.Results reveal that the temperature drift of the acceleration output bias is dominated by the sensitive mechanical stiffness.An out-of-bandwidth AC stimulus signal is introduced to excite the accelerometer,and the interference with the acceleration measurement is minimized.The demodulated phase of the excited response exhibits a monotonic relationship with the effective stiffness of the accelerometer.Through the proposed online compensation approach,the temperature drift of the effective stiffness can be detected by the demodulated phase and compensated in real time by adjusting the stiffness-tuning voltage of DSPP capacitors.The temperature drift coefficient(TDC)of the accelerometer is reduced from 0.54 to 0.29 mg/℃,and the Allan variance bias instability of about 2.8μg is not adversely affected.Meanwhile,the pull-in resulting from the temperature drift of the effective stiffness can be prevented.TDC can be further reduced to 0.04 mg/℃through an additional offline calibration based on the demodulated carrier phase representing the temperature drift of the readout circuit.展开更多
基金sponsored by Shanghai Education Commission Major Project(2017-01-07-00-07-E00052)National Natural Science Foundation of China(No.81773657)+1 种基金Shanghai Sailing Program(No.20YF1404500)Scientific Research Foundation of Huashan Hospital,Fudan University(No.2019QD012).
文摘There remain several intractable challenges for chemotherapy in glioma treatment,including the blood-brain barrier(BBB),blood-brain tumor barrier(BBTB),and tumor heterogeneity caused by cancer stem cells(CSCs),which are resistant to conventional chemotherapy.Here,we established a nano strategy to kill glioma cells and CSCs,combining carfilzomib and bis(diethyldithiocarbamate)copper.The synergistic drug combination disturbed cell protein metabolism at different stages and induced apoptosis and cuproptosis.The Y-shaped targeting ligand pHA-VAP-modified nanodiscs were designed to help the chemotherapeutic agents cross the BBB/BBTB and finally accumulate in tumor site.This all-stage targeting and all-stage treatment nanomedicine significantly prolonged the survival in glioma-bearing mice and might inspire the rational design of advanced drug delivery platforms.
基金Project supported by the Major Research Plan of the National Natural Science Foundation of China(91962211)the National Key Research and Development Program of China(2021YFC2902202)+2 种基金the Science and Technology Innovation Fund of GRINM(2022PD0102)the Major Program of Qingyuan Innovation Laboratory(00122004)the Beijing Nova Program(20230484379)。
文摘In this paper,a multi-stage leaching process for the weathered crust elution-deposited rare earth ore was proposed using MgSO_(4)as a leaching agent.The results indicate that with increasing the concentration of MgSO_(4)from 0.5 wt%-1.0 wt%to 2.0 wt%-4.0 wt%,the peak concentrations of rare earths increase from 1.87 to 3.59 to 5.49-10.21 g/L,and the collection periods of leach solution are sho rtened from 0.85 to 1.54 to 0.31-0.47(liquid-to-ore ratio).When the rare earth ore is leached with leaching agent solution with high initial pH(3.0-5.0),the rare earths and aluminum are predominantly leached by Mg^(2+)instead of H+.However,H+participate in the leaching process of rare earths and aluminum at lower initial pH(1.5-3.0)of the leaching agent solution.Especially,when the initial pH of leaching agent solution is 2.0,a large amount of aluminum is leached when the liquid-to-ore ratio is greater than 1.2.Based on the above insights,increasing the initial pH(3.0-5.0)of leaching agent solution in the injection stage using high-concentration MgSO_(4)(>1.0 wt%)can increase the peak concentration of rare earths in the leach solution and shorten the collection period.However,in the injection stage using low MgSO_(4)concentration(<1.0 wt%),an initial pH of leaching agent solution of 2.0 is selected to reduce the leaching amount of aluminum and the consumption of MgSO_(4).Comparing to the Leaching process using constant MgSO_(4)concentration(2.0 wt%,initial pH of 5.0),the leaching efficiency of rare earths using a multi-stage leaching process is approximately equal(about 94.6%)under optimal conditions.The leaching amount of aluminum is reduced by 16.9%.The consumption of MgSO_(4)is reduced by 67.1%.
基金Project supported by the Major Research Plan of the National Natural Science Foundation of China(91962211)National Key Research and Development Program of China(2018YFC1801803)+1 种基金National Natural Science Foundation of China(51804273)Major Project of Guangxi Science and Technology(Guike-AA18242022)。
文摘In order to clarify the solvent extraction and separation behaviors of rare earths and impurity of Al during the extraction and enrichment of low-concentration leach solution of ion-adsorption rare earth ore,the extraction mechanism and separation behaviors of Nd^(3+)and Al^(3+)in the Nd_(2)(SO_(4))_(3)-AI_(2)(SO_(4))_(3) mixed solution using P507 were studied in this work.The extraction of Nd^(3+)and Al^(3+)follows the cation exchange mechanism.With the increase of the equilibrium pH,β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution using P507 is always higher than that in the extraction of single Nd_(2)(SO_(4))_(3) and Al_(2)(SO_(4))_(3) solutions.It can be attributed to the fact that the extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),and Al^(3+)is more prone to be hydrolyzed at lower pH.β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution decreases gradually with the increase of mixing time within the equilibrium pH range of 1.5-1.9.The extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),but the stability of Al^(3+)-Ioaded organic phase is better than that of Nd^(3+)-loaded organic phase,thus Nd^(3+)in the Nd^(3+)-loaded organic phase is gradually replaced by Al^(3+)in the aqueous phase with the increase of mixing time.
基金Project supported by the National Natural Science Foundation of China(No.11772021)
文摘The objective of this study is to investigate the effects of the Coulomb dry friction model versus the modified Coulomb friction model on the dynamic behavior of the slider-crank mechanism with a revolute clearance joint. The normal and tangential forces acting on the contact points between the journal and the bearing are described by using a Hertzian-based contact force model and the Coulomb friction models, respectively.The dynamic equations of the mechanism are derived based on the Lagrange equations of the first kind and the Baumgarte stabilization method. The frictional force is solved via the linear complementarity problem(LCP) algorithm and the trial-and-error algorithm.Finally, three numerical examples are given to show the influence of the two Coulomb friction models on the dynamic behavior of the mechanism. Numerical results show that due to the stick friction, the slider-crank mechanism may exhibit stick-slip motion and can balance at some special positions, while the mechanism with ideal joints cannot.
基金Project supported by the National Natural Science Foundation of China(Nos.11772021 and 62073183)。
文摘The non-smooth dynamic model of an unmanned bicycle is established to study the contact-separate and stick-slip non-smooth phenomena between wheels and the ground.According to the Carvallo-Whipple configuration,the unmanned bicycle is reduced to four rigid bodies,namely,rear wheel,rear frame,front fork,and front wheel,which are connected by perfect revolute joints.The interaction between each wheel and the ground is simplified as the normal contact force and the friction force at the contact point,and these forces are described by the Hunt-Crossley contact force model and the Lu Gre friction force model,respectively.According to the characteristics of flat and curved pavements,calculation methods for contact forces and their generalized forces are presented.The dynamics of the system is modeled by the Lagrange equations of the first kind,a numerical solution algorithm of the dynamic equations is presented,and the Baumgarte stabilization method is used to restrict the drift of the constraints.The correctness of the dynamic model and the numerical algorithm is verified in comparison with the previous studies.The feasibility of the proposed model is demonstrated by simulations under different motion states.
文摘Utilization of carbon-based materials is crucial for mitigating CO_(2) emissions.However,practical materials for CO_(2) capture remain challenging due to limitations in adsorption capacity and rate.Inspired by the unique structural features of biomass materials,high-performance hierarchical porous carbon was prepared using vascular plants.The ordered arrangement structure effectively improved the adsorption capacity and rate of the material by optimizing the pore structure.Potassium hydroxide(KOH)was used as an activator to synthesize microporous carbon with an ordered hierarchical structure.The properties of hierarchical porous carbon were characterized.The experimental results indicate that porous carbon prepared from loofah complex has excellent CO_(2) adsorption capacity.The highest adsorption capacity is 4.09 mmol/g when the activation temperature is 700℃.The selectivity(15/85)for the binary gas mixture CO_(2)/N_(2) was 20,and the recoverability was good after 10 cycles.The hierarchical porous carbon derived from loofah showed excellent adsorption performance and has potential in various applications.
基金This work is supported by National Basic Research Program of China(973 Program)(No.2013CB228201).
文摘Integrating a battery energy storage system(ESS)with a large wind farm can smooth the intermittent power obtained from the wind farm,but the smoothing function will not be achieved if multiple ESSs are used to smooth the fluctuations in individual wind power plants in a distributed pattern.Therefore,this study focuses on the development of a control strategy to optimize the use of multiple ESSs to accelerate the adoption of wind energy resources.This paper proposes a quasi-automated generation control(QAGC)strategy to coordinate multiple ESSs,which responds to the grid dispatch demand rather than smoothing out the intermittent power from individual wind farms.The aims of QAGC are to ensure that multiple ESSs provide a service that is as balanced as possible,so more wind power systems at various scales can be accepted by the grid,as well maximizing the low-carbon benefits of ESSs.The effectiveness of QAGC is demonstrated by using data from an actual gigawatt scale cluster of wind plants.
基金supported by a Grant from the National Natural Science Foundation of China(Grant No.62104211).
文摘This paper presents a high-performance MEMS accelerometer with a DC/AC electrostatic stiffness tuning capability based on double-sided parallel plates(DSPPs).DC and AC electrostatic tuning enable the adjustment of the effective stiffness and the calibration of the geometric offset of the proof mass,respectively.A dynamical model of the proposed accelerometer was developed considering both DC/AC electrostatic tuning and the temperature effect.Based on the dynamical model,a self-centering closed loop is proposed for pulling the reference position of the forceto-rebalance(FTR)to the geometric center of DSPP.The self-centering accelerometer operates at the optimal reference position by eliminating the temperature drift of the readout circuit and nulling the net electrostatic tuning forces.The stiffness closed-loop is also incorporated to prevent the pull-in instability of the tuned low-stiffness accelerometer under a dramatic temperature variation.Real-time adjustments of the reference position and the DC tuning voltage are utilized to compensate for the residue temperature drift of the proposed accelerometer.As a result,a novel controlling approach composed of a self-centering closed loop,stiffness-closed loop,and temperature drift compensation is achieved for the accelerometer,realizing a temperature drift coefficient(TDC)of approximately 7μg/℃ and an Allan bias instability of less than 1μg.
基金The work is supported by the Grant of the National Natural Science Foundation of China(Grant No.62104211).
文摘This paper reports an approach of in-operation temperature bias drift compensation based on phase-based calibration for a stiffness-tunable MEMS accelerometer with double-sided parallel plate(DSPP)capacitors.The temperature drifts of the components of the accelerometer are characterized,and analytical models are built on the basis of the measured drift results.Results reveal that the temperature drift of the acceleration output bias is dominated by the sensitive mechanical stiffness.An out-of-bandwidth AC stimulus signal is introduced to excite the accelerometer,and the interference with the acceleration measurement is minimized.The demodulated phase of the excited response exhibits a monotonic relationship with the effective stiffness of the accelerometer.Through the proposed online compensation approach,the temperature drift of the effective stiffness can be detected by the demodulated phase and compensated in real time by adjusting the stiffness-tuning voltage of DSPP capacitors.The temperature drift coefficient(TDC)of the accelerometer is reduced from 0.54 to 0.29 mg/℃,and the Allan variance bias instability of about 2.8μg is not adversely affected.Meanwhile,the pull-in resulting from the temperature drift of the effective stiffness can be prevented.TDC can be further reduced to 0.04 mg/℃through an additional offline calibration based on the demodulated carrier phase representing the temperature drift of the readout circuit.
