Titania microspheres were synthesized using hydrothermal methods to exploit a new liquid chromatography stationary phase. The prepared titania microspheres were approximately 7 μm in diameter, and the particle size d...Titania microspheres were synthesized using hydrothermal methods to exploit a new liquid chromatography stationary phase. The prepared titania microspheres were approximately 7 μm in diameter, and the particle size distribution was relatively narrow and uniform. Furthermore, the average specific surface area was 276.0 m2·g·1, the average pore volume was approximately 0.25 mL·g·1, and the pore diameter was approximately 35.9 nm for sintering titania microspheres. These parameters indicate that the titania microspheres prepared for this study have excellent surface properties for chromatography. Additionally, columns filled with the titania microspheres were able to separate basic compounds, including benzene, nitrobenzene and o-nitroanisole. It could be proposed that the titania microspheres prepared for this study would be a promising stationary phase for liquid chromatography.展开更多
通过氧化石墨烯(GO)和壳聚糖(Cs)之间的氢键以及静电作用形成GO水凝胶,从而将纳米硅颗粒和碳纳米管(CNT)原位包封于其中,再经冷冻干燥及随后的热处理制得三维硅/碳纳米管/石墨烯(Si-CNT@G)纳米复合材料。采用X射线衍射(XRD)、扫描电子...通过氧化石墨烯(GO)和壳聚糖(Cs)之间的氢键以及静电作用形成GO水凝胶,从而将纳米硅颗粒和碳纳米管(CNT)原位包封于其中,再经冷冻干燥及随后的热处理制得三维硅/碳纳米管/石墨烯(Si-CNT@G)纳米复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)、热重分析(TGA)等技术对制得样品的物相、结构和微观形貌等进行了表征。结果表明,所得复合材料在CNT纵横交织的石墨烯网络中,均匀地分布着纳米硅颗粒。当作为锂离子电池的负极材料时,在两种碳介质的协同作用下,有效缓冲硅材料在充放电过程中脱/嵌锂引起的体积变化,缩短了锂离子和电子传输的距离,Si-CNT@G复合材料表现出较好的循环稳定性以及倍率性能。在500 m A·g^-1的充放电电流密度下,经过200圈循环后,其放电比容量仍高达673.7 m Ah·g^-1,容量保持率高达97%;即使将充放电电流密度升至2000 m A·g^-1时,该复合材料仍保持有566.9 m Ah·g^-1的高可逆放电比容量。独特的制备方法和优越的储锂性能,使得Si-CNT@G纳米复合材料成为理想的高性能锂离子电池负极材料的候选.展开更多
Background:As a traditional treatment method,cupping therapy is widely used in Asian countries.This overview of systematic reviews (SRs) investigated the effectiveness and safety of cupping therapy through an evidence...Background:As a traditional treatment method,cupping therapy is widely used in Asian countries.This overview of systematic reviews (SRs) investigated the effectiveness and safety of cupping therapy through an evidence-based approach.Methods:SRs that assessed the effectiveness of cupping therapy for any type of disease were searched through 6 electronic databases.Target diseases,cupping methods,numbers and types of included studies,quality of included trials,main results (including meta-analysis re sults),and authors' conclusions of SRs were extracted.The Assessment of Multiple Systematic Reviews measurement was used to evaluate methodologic quality of the SRs.Results Eight SRs met the inclusion criteria and effectiveness and safety of cupping therapy for 11 diseases were assessed.All included SRs were of good methodologic quality.However,quality of trials included in the SRs was generally poor.Meta-analysis was performed in 4 studies.Results:showed cupping therapy (alone or combined with other interventions) was better than medications (or other interventions alone) for herpes zoster,acne,facial paralysis,low back pain,or cervical spondylosis.One review reported adverse events,including hematoma,increased pain and tingling following cupping treatment.Conclusions:Cupping therapy may be beneficial for pain-related conditions,acne,and facial paralysis.However,a firm conclusion could not be drawn due to the insufficient number of included reviews and the low quality of the original studies.展开更多
BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. R...BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. Results showed that the solvents composition—volume ratio of 4-dioxane and distilled water—played the key role in the formation of BaWO4 Nanorods. Furthermore, the strong vibration at 925 cm﹣1 on its Raman spectrum indicated that the BaWO4 nanorods is good at stimulating Raman scattering in transient and steady-state, making it as a promising candidate material for laser with self-raman conversion of radiation inside the active medium.展开更多
The metasurface is a platform with a small footprint and abundant functionalities.With propagation phase and geometric phase,polarization multiplexing is possible.However,different response behaviors of propagation ph...The metasurface is a platform with a small footprint and abundant functionalities.With propagation phase and geometric phase,polarization multiplexing is possible.However,different response behaviors of propagation phase and geometric phase to wavelength have not been fully employed to widen the capabilities of metasurfaces.Here,we theoretically demonstrate that metasurfaces can achieve near-field and far-field decoupling with the same polarization at two wavelengths.First,we found a set of pillars whose propagation phase difference between two wavelengths covers the full range of 2π.Then,by rotating pillars to control the geometric phase,the phase at both wavelengths can cover the full range of 2π.Finally,by means of interference principle,arbitrary independent coding for the near field and far field of dual wavelengths is realized.In addition,when the far-field function is focusing,the focused spot is close to the diffraction limit,and,when the NA of the lens is very small,the final output focal length is four times of initial input focal length.This work circumvents the strong wavelength-dependent limitation of planar devices and paves the way toward designing multi-wavelength and multi-functional metadevices for scenarios such as AR applications,fluorescence microscopy,and stimulated emission depletion microscopy.展开更多
文摘Titania microspheres were synthesized using hydrothermal methods to exploit a new liquid chromatography stationary phase. The prepared titania microspheres were approximately 7 μm in diameter, and the particle size distribution was relatively narrow and uniform. Furthermore, the average specific surface area was 276.0 m2·g·1, the average pore volume was approximately 0.25 mL·g·1, and the pore diameter was approximately 35.9 nm for sintering titania microspheres. These parameters indicate that the titania microspheres prepared for this study have excellent surface properties for chromatography. Additionally, columns filled with the titania microspheres were able to separate basic compounds, including benzene, nitrobenzene and o-nitroanisole. It could be proposed that the titania microspheres prepared for this study would be a promising stationary phase for liquid chromatography.
文摘通过氧化石墨烯(GO)和壳聚糖(Cs)之间的氢键以及静电作用形成GO水凝胶,从而将纳米硅颗粒和碳纳米管(CNT)原位包封于其中,再经冷冻干燥及随后的热处理制得三维硅/碳纳米管/石墨烯(Si-CNT@G)纳米复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)、热重分析(TGA)等技术对制得样品的物相、结构和微观形貌等进行了表征。结果表明,所得复合材料在CNT纵横交织的石墨烯网络中,均匀地分布着纳米硅颗粒。当作为锂离子电池的负极材料时,在两种碳介质的协同作用下,有效缓冲硅材料在充放电过程中脱/嵌锂引起的体积变化,缩短了锂离子和电子传输的距离,Si-CNT@G复合材料表现出较好的循环稳定性以及倍率性能。在500 m A·g^-1的充放电电流密度下,经过200圈循环后,其放电比容量仍高达673.7 m Ah·g^-1,容量保持率高达97%;即使将充放电电流密度升至2000 m A·g^-1时,该复合材料仍保持有566.9 m Ah·g^-1的高可逆放电比容量。独特的制备方法和优越的储锂性能,使得Si-CNT@G纳米复合材料成为理想的高性能锂离子电池负极材料的候选.
基金Huijuan Cao,Mei Han,and Jianping Liu are supported by the Research Capacity Establishment Grant(No.2013-ZDXKKF)the Innovative Research Team(No.2011-CXTD-09)from the Beijing University of Chinese Medicine.
文摘Background:As a traditional treatment method,cupping therapy is widely used in Asian countries.This overview of systematic reviews (SRs) investigated the effectiveness and safety of cupping therapy through an evidence-based approach.Methods:SRs that assessed the effectiveness of cupping therapy for any type of disease were searched through 6 electronic databases.Target diseases,cupping methods,numbers and types of included studies,quality of included trials,main results (including meta-analysis re sults),and authors' conclusions of SRs were extracted.The Assessment of Multiple Systematic Reviews measurement was used to evaluate methodologic quality of the SRs.Results Eight SRs met the inclusion criteria and effectiveness and safety of cupping therapy for 11 diseases were assessed.All included SRs were of good methodologic quality.However,quality of trials included in the SRs was generally poor.Meta-analysis was performed in 4 studies.Results:showed cupping therapy (alone or combined with other interventions) was better than medications (or other interventions alone) for herpes zoster,acne,facial paralysis,low back pain,or cervical spondylosis.One review reported adverse events,including hematoma,increased pain and tingling following cupping treatment.Conclusions:Cupping therapy may be beneficial for pain-related conditions,acne,and facial paralysis.However,a firm conclusion could not be drawn due to the insufficient number of included reviews and the low quality of the original studies.
文摘BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. Results showed that the solvents composition—volume ratio of 4-dioxane and distilled water—played the key role in the formation of BaWO4 Nanorods. Furthermore, the strong vibration at 925 cm﹣1 on its Raman spectrum indicated that the BaWO4 nanorods is good at stimulating Raman scattering in transient and steady-state, making it as a promising candidate material for laser with self-raman conversion of radiation inside the active medium.
基金supported by the National Key Research and Development Program of China(No.2017YFA0303700)National Natural Science Foundation of China(Nos.11621091,11822406,11834007,11774164,and 11774162)Fundamental Research Funds for the Central Universities(No.020414380175)。
文摘The metasurface is a platform with a small footprint and abundant functionalities.With propagation phase and geometric phase,polarization multiplexing is possible.However,different response behaviors of propagation phase and geometric phase to wavelength have not been fully employed to widen the capabilities of metasurfaces.Here,we theoretically demonstrate that metasurfaces can achieve near-field and far-field decoupling with the same polarization at two wavelengths.First,we found a set of pillars whose propagation phase difference between two wavelengths covers the full range of 2π.Then,by rotating pillars to control the geometric phase,the phase at both wavelengths can cover the full range of 2π.Finally,by means of interference principle,arbitrary independent coding for the near field and far field of dual wavelengths is realized.In addition,when the far-field function is focusing,the focused spot is close to the diffraction limit,and,when the NA of the lens is very small,the final output focal length is four times of initial input focal length.This work circumvents the strong wavelength-dependent limitation of planar devices and paves the way toward designing multi-wavelength and multi-functional metadevices for scenarios such as AR applications,fluorescence microscopy,and stimulated emission depletion microscopy.
