The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these t...The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these techniques of the hair surfaces allows us to observe and study some marble fragments that can originate from the walls of the sarcophagus in which Maria-Magdalena’s remains were kept. These new findings support the authenticity of the hair as traditionally reported in the French “tradition des Saints de Provence”.展开更多
The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts a...The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts as a low-pass filter, and the biochemical signals are nonlinearly modulated by the pulsatile flows, which depend on the biochemical signal frequency, the flow signal frequency, and the biochemical signal transporting distance. It is concluded that, the transfer characteristics of the dynamic biochemical signals, which are transported in the time-varying flows, should be carefully considered for better loading biochemical signals on the cells cultured on the bottom of the microfluidic channel.展开更多
A reproducing kernel collocation method based on strong formulation is introduced for transient dynamics. To study the stability property of this method, an algorithm based on the von Neumann hypothesis is proposed to...A reproducing kernel collocation method based on strong formulation is introduced for transient dynamics. To study the stability property of this method, an algorithm based on the von Neumann hypothesis is proposed to predict the critical time step. A numerical test is conducted to validate the algorithm. The numerical critical time step and the predicted critical time step are in good agreement. The results are compared with those obtained based on the radial basis collocation method, and they axe in good agreement. Several important conclusions for choosing a proper support size of the reproducing kernel shape function are given to improve the stability condition.展开更多
The effect of copper concentration on the performance of the catalytic reaction between silicon and methyl chloride was investigated using online gas chromatogram. The catalyst concentration greatly influences various...The effect of copper concentration on the performance of the catalytic reaction between silicon and methyl chloride was investigated using online gas chromatogram. The catalyst concentration greatly influences various aspects of the direct organosilane synthesis process, including the reaction rate, the selec- tivity, and the silicon conversion. The reaction activity and the silicon conversion increase as the catalyst concentration increases. However, the reaction selectivity decreases for the catalyst concentrations more .than 9 wt.%. The cross-sections of deactivated contact mass particles were observed by optical microscopy and analyzed by scanning electron microscope combined with energy dispersive X-ray detector （SEM-EDX） The observations showed that a textured substance formed on the original flat surface of the silicon particles after deactivation with copper only in a shallow surface layer of the contact mass. This indicates that the copper diffusion is the rate limiting step which causes the reaction deactivation.展开更多
Numerically solving 3D seismic wave equations is a key requirement for forward modeling and inversion.Here,we propose a weighted Runge-Kutta dis-continuous Galerkin(WRKDG)method for 3D acoustic and elastic wave-field ...Numerically solving 3D seismic wave equations is a key requirement for forward modeling and inversion.Here,we propose a weighted Runge-Kutta dis-continuous Galerkin(WRKDG)method for 3D acoustic and elastic wave-field mod-eling.For this method,the second-order seismic wave equations in 3D heteroge-neous anisotropic media are transformed into a first-order hyperbolic system,and then we use a discontinuous Galerkin(DG)solver based on numerical-flux formulations for spatial discretization.The time discretization is based on an implicit di-agonal Runge-Kutta(RK)method and an explicit iterative technique,which avoids solving a large-scale system of linear equations.In the iterative process,we introduce a weighting factor.We investigate the numerical stability criteria of the 3D method in detail for linear and quadratic spatial basis functions.We also present a 3D analysis of numerical dispersion for the full discrete approximation of acoustic equation,which demonstrates that the WRKDG method can efficiently suppress numerical dispersion on coarse grids.Numerical results for several different 3D models including homogeneous and heterogeneous media with isotropic and anisotropic cases show that the 3D WRKDG method can effectively suppress numerical dispersion and provide accurate wave-field information on coarse mesh.展开更多
We proposed and demonstrated the generation and transmission of 10-Gbps retum-to-zero ON/OFF keying （RZ-OOK） signal using a new technique without pulse carving at transmitter. The new technique is characterized by a...We proposed and demonstrated the generation and transmission of 10-Gbps retum-to-zero ON/OFF keying （RZ-OOK） signal using a new technique without pulse carving at transmitter. The new technique is characterized by a 3 dB built-in gain with better tolerance for chromatic dispersion in standard single mode fiber （SSMF）. Fiber Bragg grating （FBG） is used as chromatic dispersion compensating device to investigate the toler- ance of the proposed scheme. The simulation model of wavelength division multiplexing （WDM） based on OptiSystem.v.8.0 is presented. Simulation results show that there are error free transmission performance in a distance of 600 km with negligible power penalty and improved receiver sensitivity compared to conventional pulse carving approach.展开更多
In this study,two different methods were applied to disperse hollow silica nanoparticles(HSNP);one employed polyethylenimine(PEI)as the dispersant during the synthesis processes for preparing HSNP,while the other adde...In this study,two different methods were applied to disperse hollow silica nanoparticles(HSNP);one employed polyethylenimine(PEI)as the dispersant during the synthesis processes for preparing HSNP,while the other added PEI into suspensions of the prepared HSNP and used milling treatment to achieve the desired dispersion.It was found that adding PEI during the synthesis process of HSNP had no noticeable improvement in the dispersion,while adding PEI into suspen-sions of the prepared HSNP and utilizing milling treatment resulted in remarkable dispersion improvement.Therefore,the latter was chosen as the method in dispersing HSNP suspensions.The adsorption of PEI on the surface of HSNP and the stability of the aqueous suspensions was investigated.The results indicated that the adsorption of PEI on the surface of HSNP would increase the repulsive energy among particles,hence reducing the agglomeration of HSNP and improving the stability of the aqueous suspensions.The change of HSNP’s ■ potential after adding PEI and the rela-tionship between the adsorbed amount of PEI and pH were also investigated.展开更多
文摘The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these techniques of the hair surfaces allows us to observe and study some marble fragments that can originate from the walls of the sarcophagus in which Maria-Magdalena’s remains were kept. These new findings support the authenticity of the hair as traditionally reported in the French “tradition des Saints de Provence”.
基金Project supported by the National Natural Science Foundation of China(Nos.11172060 and11672065)
文摘The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts as a low-pass filter, and the biochemical signals are nonlinearly modulated by the pulsatile flows, which depend on the biochemical signal frequency, the flow signal frequency, and the biochemical signal transporting distance. It is concluded that, the transfer characteristics of the dynamic biochemical signals, which are transported in the time-varying flows, should be carefully considered for better loading biochemical signals on the cells cultured on the bottom of the microfluidic channel.
基金Project supported by the Western Transport Technical Project of Ministry of Transport of China(No. 2009318000046)
文摘A reproducing kernel collocation method based on strong formulation is introduced for transient dynamics. To study the stability property of this method, an algorithm based on the von Neumann hypothesis is proposed to predict the critical time step. A numerical test is conducted to validate the algorithm. The numerical critical time step and the predicted critical time step are in good agreement. The results are compared with those obtained based on the radial basis collocation method, and they axe in good agreement. Several important conclusions for choosing a proper support size of the reproducing kernel shape function are given to improve the stability condition.
文摘The effect of copper concentration on the performance of the catalytic reaction between silicon and methyl chloride was investigated using online gas chromatogram. The catalyst concentration greatly influences various aspects of the direct organosilane synthesis process, including the reaction rate, the selec- tivity, and the silicon conversion. The reaction activity and the silicon conversion increase as the catalyst concentration increases. However, the reaction selectivity decreases for the catalyst concentrations more .than 9 wt.%. The cross-sections of deactivated contact mass particles were observed by optical microscopy and analyzed by scanning electron microscope combined with energy dispersive X-ray detector （SEM-EDX） The observations showed that a textured substance formed on the original flat surface of the silicon particles after deactivation with copper only in a shallow surface layer of the contact mass. This indicates that the copper diffusion is the rate limiting step which causes the reaction deactivation.
基金supported by the Hainan Provincial Natural Science Foundation of China(Grant No.418QN205)the National Natural Science Foundation of China(Grant Nos.41604090,91730306)+1 种基金the National Key R&D Program on Monitoring,Early Warning and Prevention of Major Natural Disaster(Grant No.2017YFC1500301)by the Statoil Company(Contract No.4503294711).
文摘Numerically solving 3D seismic wave equations is a key requirement for forward modeling and inversion.Here,we propose a weighted Runge-Kutta dis-continuous Galerkin(WRKDG)method for 3D acoustic and elastic wave-field mod-eling.For this method,the second-order seismic wave equations in 3D heteroge-neous anisotropic media are transformed into a first-order hyperbolic system,and then we use a discontinuous Galerkin(DG)solver based on numerical-flux formulations for spatial discretization.The time discretization is based on an implicit di-agonal Runge-Kutta(RK)method and an explicit iterative technique,which avoids solving a large-scale system of linear equations.In the iterative process,we introduce a weighting factor.We investigate the numerical stability criteria of the 3D method in detail for linear and quadratic spatial basis functions.We also present a 3D analysis of numerical dispersion for the full discrete approximation of acoustic equation,which demonstrates that the WRKDG method can efficiently suppress numerical dispersion on coarse grids.Numerical results for several different 3D models including homogeneous and heterogeneous media with isotropic and anisotropic cases show that the 3D WRKDG method can effectively suppress numerical dispersion and provide accurate wave-field information on coarse mesh.
文摘We proposed and demonstrated the generation and transmission of 10-Gbps retum-to-zero ON/OFF keying （RZ-OOK） signal using a new technique without pulse carving at transmitter. The new technique is characterized by a 3 dB built-in gain with better tolerance for chromatic dispersion in standard single mode fiber （SSMF）. Fiber Bragg grating （FBG） is used as chromatic dispersion compensating device to investigate the toler- ance of the proposed scheme. The simulation model of wavelength division multiplexing （WDM） based on OptiSystem.v.8.0 is presented. Simulation results show that there are error free transmission performance in a distance of 600 km with negligible power penalty and improved receiver sensitivity compared to conventional pulse carving approach.
基金supported by the National Natural Science Foundation of China(Grant Nos.20506001 and 20236020)the Program for New Century Excellent Talents in University(Grant No.NCET-04-0123)Beijing Municipal Commission of Education(Grant No.JD100100403).
文摘In this study,two different methods were applied to disperse hollow silica nanoparticles(HSNP);one employed polyethylenimine(PEI)as the dispersant during the synthesis processes for preparing HSNP,while the other added PEI into suspensions of the prepared HSNP and used milling treatment to achieve the desired dispersion.It was found that adding PEI during the synthesis process of HSNP had no noticeable improvement in the dispersion,while adding PEI into suspen-sions of the prepared HSNP and utilizing milling treatment resulted in remarkable dispersion improvement.Therefore,the latter was chosen as the method in dispersing HSNP suspensions.The adsorption of PEI on the surface of HSNP and the stability of the aqueous suspensions was investigated.The results indicated that the adsorption of PEI on the surface of HSNP would increase the repulsive energy among particles,hence reducing the agglomeration of HSNP and improving the stability of the aqueous suspensions.The change of HSNP’s ■ potential after adding PEI and the rela-tionship between the adsorbed amount of PEI and pH were also investigated.
