The Li-Mg-N-H(Mg(NH_(2))_(2)-2LiH)system,as a high-capacity Mg-based metal hydrogen storage material(5.6 wt%),has broad prospects for in vehicle hydrogen storage applications,but it still has high hydrogen ab/desorpti...The Li-Mg-N-H(Mg(NH_(2))_(2)-2LiH)system,as a high-capacity Mg-based metal hydrogen storage material(5.6 wt%),has broad prospects for in vehicle hydrogen storage applications,but it still has high hydrogen ab/desorption barriers.To improve its hydrogen storage performance,a nanohydrogen storage alloy was innovatively combined with Mg(NH_(2))_(2)-2LiH,AB5 type nanohydrogen storage alloy LaNi_(5)was prepared by co-precipitation method.Nano LaNi_(5)and single-walled carbon nanotubes(SWCNTs)were co-doped into the Mg(NH_(2))_(2)-2LiH system at a ratio of 10 wt%and 2 wt%,significantly enhancing the hydrogen storage performance of Mg(NH_(2))_(2)-2LiH.The initial hydrogen ab/desorption temperatures of the co-doped system decreased from110/130℃to 45/85℃.The release of by-product ammonia is significantly inhibited.4.73 wt% H_(2)can be ab/desorption in 150 min at 180/170℃.Cycle tests show that the co-doped system can still maintain a hydrogen storage capacity of 4.75 wt% after ten hydrogen release cycles.Mechanism and density functional theory study have shown that during the hydrogen release process,partially hydrogenated LaNi_(5)weakens the chemical bonding in Mg(NH_(2))_(2),promoted the dissociation of hydrogen from the Mg(NH_(2))_(2)-2LiH system,while playing a dual role of"hydrogen overflow"and"hydrogen pump".SWCNTs act as auxiliary agents,helping to refine particle size and increase thermal conductivity.The synergistic effect of the two optimizes the comprehensive hydrogen storage performance of Mg(NH_(2))_(2)-2LiH.This study provides a new research method for improving the comprehensive hydrogen storage performance of Mg-based metal hydrogen storage materials using rare earth element catalysts.展开更多
In this paper, different models of parallel Carbon nanotube Bundles are carried out and simulated. In the first place, a model of three parallel SWCNT （singe walled carbon nanotube） Bundles and DWCNT （double walled...In this paper, different models of parallel Carbon nanotube Bundles are carried out and simulated. In the first place, a model of three parallel SWCNT （singe walled carbon nanotube） Bundles and DWCNT （double walled carbon nanotube） Bundles was established and simulated. It has been noticed that the variation on the number of Carbon nanotubes in the bundle has an impact on the crosstalk amplitude. In the second place, a model of three parallel MWCNT （multi walled carbon nanotube） Bundles was established and simulated and the crosstalk effect has been noticed and compared with SWCNT/DWCNT Bundles. Finally a model of mixed Bundles （Single-Double-Single） and （Double-Single-Double） was carried out and simulated. All simulations were established using Pspice.展开更多
A new SnO2-Fe2O3/SWCNTs（single-walled carbon nanotubes） ternary nanocomposite was first synthesized by a facile hydrothermal approach.SnO2 and Fe2O3 nanoparticles（NPs） were homogeneously located on the surface of ...A new SnO2-Fe2O3/SWCNTs（single-walled carbon nanotubes） ternary nanocomposite was first synthesized by a facile hydrothermal approach.SnO2 and Fe2O3 nanoparticles（NPs） were homogeneously located on the surface of SWCNTs,as confirmed by X-ray diffraction（XRD）,transmission electron microscope（TEM） and energy dispersive X-ray spectroscopy（EDX）.Due to the synergistic effect of different components,the as synthesized SnO2-Fe2O3/SWCNTs composite as an anode material for lithium-ion batteries exhibited excellent electrochemical performance with a high capacity of 692 mAh·g-1 which could be maintained after 50 cycles at 200 mA·g-1.Even at a high rate of2000 mA·g-1,the capacity was still remained at 656 mAh·g-1.展开更多
In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is ...In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is performed in the presence of an internal heat source and thermal radiation phenomena. The thermal conductivity of base fluid water is strengthened by considering the carbon nanotubes (CNTs). Mathematical formulation operated, results in a set of non-linear coupled partial differential equations. The governed differential system is transformed into an ordinary differential system by considering suitable similarity variables. Exact solutions in the closed form are computed for the temperature, momentum and pressure gradient profiles. In this study, special attention is devoted to the electrical conductivity of the CNTs. Streamlines patterns are also discussed to witness the flow lines for different parameters. Thermodynamics analysis shows that entropy of the current flow system is an increasing function of Brinkmann number, magnetic parameter, nanoparticle concentration parameter and Darcy number.展开更多
This work aims to study magnetohydrodynamic flow through a circular cylinder in a horizontal position of SWCNTs in blood as a base fluid in the existence of non-linear thermal radiation and heat source/sink.Three kind...This work aims to study magnetohydrodynamic flow through a circular cylinder in a horizontal position of SWCNTs in blood as a base fluid in the existence of non-linear thermal radiation and heat source/sink.Three kinds of nanoparticles shapes are considered.The study is employed the finite element technique to explore and enhance the influences of essential parameters on temperature profiles and is debated the heat transport within blood injects with SWCNTs and exposes to electromagnetic radiation.The treatment with thermal analysis and heat transfer rate being a better substitute more than surgery and chemotherapy for cancer therapy.Utilizing of nanoparticles thermal features is a mounting area of nanomedicine field because of the probable for purposeful demolition of cancer cells.This remedy is relied on many parameters,including nanofluid thermal conductivity,nanoparticles volume fraction,thermal radiation and power and heat source.The numerical solutions for flow and heat transfer features are assessed for diverse governing parameters values.The obtained results are substantiated against the relevant numerical results in the published researches.Results show that both flow velocity and temperature increase for larger values of thermal radiation,heat source and SWCNTs volume fraction with lamina and cylinder shapes.Also,spherical shape of SWCNTs occurs high disturbances in velocity and temperature distribution in the case of cooled cylinder.展开更多
A novel solid Bronsted-Lewis acid catalyst La-PW-SiO_(2)/SWCNTs(single-wall carbon nanotubes)was synthesized from the synergistic modification of H_(3)PW_(12)O_(40)(HPW)by single-walled carbon nanotubes functionalized...A novel solid Bronsted-Lewis acid catalyst La-PW-SiO_(2)/SWCNTs(single-wall carbon nanotubes)was synthesized from the synergistic modification of H_(3)PW_(12)O_(40)(HPW)by single-walled carbon nanotubes functionalized with sidewall hydroxyl groups(SWCNTs–OH)and La^(3+) via sol–gel method.The freshly prepared catalyst was characterized by several methods,and the catalytic activity and stability of it were studied from the esterification of oleic acid and methanol.Results showed that the highest conversion of oleic acid was 93.1%(mass)and maintained as high as 88.7%(mass)after six cycles of La-PW-SiO_(2)/SWCNTs.The high catalytic activity and stability of La-PW-SiO_(2)/SWCNTs can be attributed to the strong electron withdrawing effect of La^(3+) on π bond of SWCNTs,because it can facilitate the formation of a large number of strong Lewis acid sites.Therefore,the reduction of catalytic activity of a solid acid catalyst due to the fact that hydration reaction of its Bronsted acid sites can be effectively reduced.La-PW-SiO_(2)/SWCNTs can be an efficient and economical catalyst,because it shows good catalytic activity and stability.展开更多
Phenolic compounds have become one kind of the important pollutants of the marine environment. Single-walled Carbon nanotubes, as one-dimensional nano materials, have light weight and perfect hexagonal structure of co...Phenolic compounds have become one kind of the important pollutants of the marine environment. Single-walled Carbon nanotubes, as one-dimensional nano materials, have light weight and perfect hexagonal structure of connections, with many unusual mechanical, chemical and electrical properties. In recent years, with the research of carbon nanotubes and other nano materials, the application prospect is also constantly discussed. In this paper, homemade single-walled carbon nanotubes(SWCNTs) coating was used for establishing an analytical approach to the determination of five kinds of phenolic compounds in seawater using SPME-GC-MS. Optimal conditions: After saturation was conducted with Na Cl, and p H was adjusted to 2.0 with H_2SO_4, the extract was immersed in a water bath at 40 for GC℃-MS determination through 40-min agitating extraction at 500 rmin^(-1) and 3-min desorption at 280℃. The liniearities ranged between 0.01-100 μg L^(-1), and the determination limits ranged between 1.5-10 ngL^(-1). The relative standard deviation(RSD, n = 5) was less than 6.5%. For the phenolic compounds obtained from the spiked recovery test for actual seawater samples, the rates of recovery were 87.5%-101.7%, and the RSDs were less than 8.8%, which met the requirements of determination. Due to its simplicity, high efficiency and low consumption, this approach is suitable for the analysis of trace amounts of phenolic compounds in marine waters.展开更多
针对在室温环境下探测瓦斯浓度,提出一种基于钯掺杂单壁碳纳米管(Pd-SWCNTs)的超宽带射频识别(UWB-RFID)传感器。传感器为薄型标签,由传感探头和电磁界面组成,其中传感探头为一PdSWCNTs加载的交叉指型电极(IDE);电磁界面由天线、微带线...针对在室温环境下探测瓦斯浓度,提出一种基于钯掺杂单壁碳纳米管(Pd-SWCNTs)的超宽带射频识别(UWB-RFID)传感器。传感器为薄型标签,由传感探头和电磁界面组成,其中传感探头为一PdSWCNTs加载的交叉指型电极(IDE);电磁界面由天线、微带线和终端负载组成。Pd-SWCNTs感知瓦斯浓度,引起IDE电流的变化,形成带隙幅度调制和带隙频率调制两种识别模式。当瓦斯浓度从0×10-6增加到100×10-6,基于带隙调幅调制的识别灵敏度为-9.32 d B;而基于带隙调频调制的识别灵敏度为-11.30 d B。展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51971199 and 51771171)
文摘The Li-Mg-N-H(Mg(NH_(2))_(2)-2LiH)system,as a high-capacity Mg-based metal hydrogen storage material(5.6 wt%),has broad prospects for in vehicle hydrogen storage applications,but it still has high hydrogen ab/desorption barriers.To improve its hydrogen storage performance,a nanohydrogen storage alloy was innovatively combined with Mg(NH_(2))_(2)-2LiH,AB5 type nanohydrogen storage alloy LaNi_(5)was prepared by co-precipitation method.Nano LaNi_(5)and single-walled carbon nanotubes(SWCNTs)were co-doped into the Mg(NH_(2))_(2)-2LiH system at a ratio of 10 wt%and 2 wt%,significantly enhancing the hydrogen storage performance of Mg(NH_(2))_(2)-2LiH.The initial hydrogen ab/desorption temperatures of the co-doped system decreased from110/130℃to 45/85℃.The release of by-product ammonia is significantly inhibited.4.73 wt% H_(2)can be ab/desorption in 150 min at 180/170℃.Cycle tests show that the co-doped system can still maintain a hydrogen storage capacity of 4.75 wt% after ten hydrogen release cycles.Mechanism and density functional theory study have shown that during the hydrogen release process,partially hydrogenated LaNi_(5)weakens the chemical bonding in Mg(NH_(2))_(2),promoted the dissociation of hydrogen from the Mg(NH_(2))_(2)-2LiH system,while playing a dual role of"hydrogen overflow"and"hydrogen pump".SWCNTs act as auxiliary agents,helping to refine particle size and increase thermal conductivity.The synergistic effect of the two optimizes the comprehensive hydrogen storage performance of Mg(NH_(2))_(2)-2LiH.This study provides a new research method for improving the comprehensive hydrogen storage performance of Mg-based metal hydrogen storage materials using rare earth element catalysts.
文摘In this paper, different models of parallel Carbon nanotube Bundles are carried out and simulated. In the first place, a model of three parallel SWCNT （singe walled carbon nanotube） Bundles and DWCNT （double walled carbon nanotube） Bundles was established and simulated. It has been noticed that the variation on the number of Carbon nanotubes in the bundle has an impact on the crosstalk amplitude. In the second place, a model of three parallel MWCNT （multi walled carbon nanotube） Bundles was established and simulated and the crosstalk effect has been noticed and compared with SWCNT/DWCNT Bundles. Finally a model of mixed Bundles （Single-Double-Single） and （Double-Single-Double） was carried out and simulated. All simulations were established using Pspice.
基金supported by the National Key Project on Basic Research(Grant No.2011CB935904)the National Natural Science Foundation of China(Grant No.21171163,91127020)NSF for Distinguished Young Scholars of Fujian Province(Grant No.2013J06006)
文摘A new SnO2-Fe2O3/SWCNTs（single-walled carbon nanotubes） ternary nanocomposite was first synthesized by a facile hydrothermal approach.SnO2 and Fe2O3 nanoparticles（NPs） were homogeneously located on the surface of SWCNTs,as confirmed by X-ray diffraction（XRD）,transmission electron microscope（TEM） and energy dispersive X-ray spectroscopy（EDX）.Due to the synergistic effect of different components,the as synthesized SnO2-Fe2O3/SWCNTs composite as an anode material for lithium-ion batteries exhibited excellent electrochemical performance with a high capacity of 692 mAh·g-1 which could be maintained after 50 cycles at 200 mA·g-1.Even at a high rate of2000 mA·g-1,the capacity was still remained at 656 mAh·g-1.
文摘In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is performed in the presence of an internal heat source and thermal radiation phenomena. The thermal conductivity of base fluid water is strengthened by considering the carbon nanotubes (CNTs). Mathematical formulation operated, results in a set of non-linear coupled partial differential equations. The governed differential system is transformed into an ordinary differential system by considering suitable similarity variables. Exact solutions in the closed form are computed for the temperature, momentum and pressure gradient profiles. In this study, special attention is devoted to the electrical conductivity of the CNTs. Streamlines patterns are also discussed to witness the flow lines for different parameters. Thermodynamics analysis shows that entropy of the current flow system is an increasing function of Brinkmann number, magnetic parameter, nanoparticle concentration parameter and Darcy number.
基金Supported by Deanship of Scientific Research,Northern Border University under Grant No.SCI-2018-3-9-F-7614,KSA
文摘This work aims to study magnetohydrodynamic flow through a circular cylinder in a horizontal position of SWCNTs in blood as a base fluid in the existence of non-linear thermal radiation and heat source/sink.Three kinds of nanoparticles shapes are considered.The study is employed the finite element technique to explore and enhance the influences of essential parameters on temperature profiles and is debated the heat transport within blood injects with SWCNTs and exposes to electromagnetic radiation.The treatment with thermal analysis and heat transfer rate being a better substitute more than surgery and chemotherapy for cancer therapy.Utilizing of nanoparticles thermal features is a mounting area of nanomedicine field because of the probable for purposeful demolition of cancer cells.This remedy is relied on many parameters,including nanofluid thermal conductivity,nanoparticles volume fraction,thermal radiation and power and heat source.The numerical solutions for flow and heat transfer features are assessed for diverse governing parameters values.The obtained results are substantiated against the relevant numerical results in the published researches.Results show that both flow velocity and temperature increase for larger values of thermal radiation,heat source and SWCNTs volume fraction with lamina and cylinder shapes.Also,spherical shape of SWCNTs occurs high disturbances in velocity and temperature distribution in the case of cooled cylinder.
基金supported by the National Natural Science Foundation of China(21766009)Program of Qingjiang Excellent Young Talents(Jiangxi University of Science and Technology)。
文摘A novel solid Bronsted-Lewis acid catalyst La-PW-SiO_(2)/SWCNTs(single-wall carbon nanotubes)was synthesized from the synergistic modification of H_(3)PW_(12)O_(40)(HPW)by single-walled carbon nanotubes functionalized with sidewall hydroxyl groups(SWCNTs–OH)and La^(3+) via sol–gel method.The freshly prepared catalyst was characterized by several methods,and the catalytic activity and stability of it were studied from the esterification of oleic acid and methanol.Results showed that the highest conversion of oleic acid was 93.1%(mass)and maintained as high as 88.7%(mass)after six cycles of La-PW-SiO_(2)/SWCNTs.The high catalytic activity and stability of La-PW-SiO_(2)/SWCNTs can be attributed to the strong electron withdrawing effect of La^(3+) on π bond of SWCNTs,because it can facilitate the formation of a large number of strong Lewis acid sites.Therefore,the reduction of catalytic activity of a solid acid catalyst due to the fact that hydration reaction of its Bronsted acid sites can be effectively reduced.La-PW-SiO_(2)/SWCNTs can be an efficient and economical catalyst,because it shows good catalytic activity and stability.
基金supported by the Fund project: Marine Project Special Public Welfare Industry Scientific Research Funds (201405037)
文摘Phenolic compounds have become one kind of the important pollutants of the marine environment. Single-walled Carbon nanotubes, as one-dimensional nano materials, have light weight and perfect hexagonal structure of connections, with many unusual mechanical, chemical and electrical properties. In recent years, with the research of carbon nanotubes and other nano materials, the application prospect is also constantly discussed. In this paper, homemade single-walled carbon nanotubes(SWCNTs) coating was used for establishing an analytical approach to the determination of five kinds of phenolic compounds in seawater using SPME-GC-MS. Optimal conditions: After saturation was conducted with Na Cl, and p H was adjusted to 2.0 with H_2SO_4, the extract was immersed in a water bath at 40 for GC℃-MS determination through 40-min agitating extraction at 500 rmin^(-1) and 3-min desorption at 280℃. The liniearities ranged between 0.01-100 μg L^(-1), and the determination limits ranged between 1.5-10 ngL^(-1). The relative standard deviation(RSD, n = 5) was less than 6.5%. For the phenolic compounds obtained from the spiked recovery test for actual seawater samples, the rates of recovery were 87.5%-101.7%, and the RSDs were less than 8.8%, which met the requirements of determination. Due to its simplicity, high efficiency and low consumption, this approach is suitable for the analysis of trace amounts of phenolic compounds in marine waters.
文摘针对在室温环境下探测瓦斯浓度,提出一种基于钯掺杂单壁碳纳米管(Pd-SWCNTs)的超宽带射频识别(UWB-RFID)传感器。传感器为薄型标签,由传感探头和电磁界面组成,其中传感探头为一PdSWCNTs加载的交叉指型电极(IDE);电磁界面由天线、微带线和终端负载组成。Pd-SWCNTs感知瓦斯浓度,引起IDE电流的变化,形成带隙幅度调制和带隙频率调制两种识别模式。当瓦斯浓度从0×10-6增加到100×10-6,基于带隙调幅调制的识别灵敏度为-9.32 d B;而基于带隙调频调制的识别灵敏度为-11.30 d B。
