Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] ...Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] direction, and the main exposed facet is the （720） crystal plane. The HUWNRs exhibit good electrochemical performance as an anode material in lithium ion batteries because of their unique structure. It is believed that these unique materials may be applied in many fields.展开更多
This paper aims at investigating the resonance frequencies and stability of a long Graphene Nano-Ribbon(GNR)carrying electric current.The governing equation of motion is obtained based on the Euler-Bernoulli beam mode...This paper aims at investigating the resonance frequencies and stability of a long Graphene Nano-Ribbon(GNR)carrying electric current.The governing equation of motion is obtained based on the Euler-Bernoulli beam model along with Hamilton’s principle.The transverse force distribution on the GNR due to the interaction of the electric current with its own magnetic field is determined by the Biot-Savart and Lorentz force laws.Using Galerkin’s method,the governing equation is solved and the effect of current strength and dimensions of the GNR on the stability and resonance frequencies are investigated.展开更多
采用热化学气相沉积法(thermal chemical vapor deposition,TCVD)在经过高温氨气处理后的硅基铁纳米薄膜表面实现片状碳纳米带的催化生长。通过场发射扫描电子显微镜(field emission scanning electron microscopy,FESEM)的观察可知,生...采用热化学气相沉积法(thermal chemical vapor deposition,TCVD)在经过高温氨气处理后的硅基铁纳米薄膜表面实现片状碳纳米带的催化生长。通过场发射扫描电子显微镜(field emission scanning electron microscopy,FESEM)的观察可知,生成的碳材料是一种准二维材料,表面具有垂直于其长度方向的纹理,厚(z方向)约几十纳米,宽(y方向)几百纳米,类似于一种"搓板"状的结构。而其宽度沿着其长度方向则有较大的变化,时宽时窄,没有固定的规律。这种带状碳纳米纤维材料的边缘光滑,比中间略宽,类似于一种镶边结构。通过高分辨透射电子显微镜(high resolution transmission electron microscopy,HRTEM)的观察可知,碳纳米带的碳层沿着垂直于碳纳米带长度的(002)方向有统一的排列,其边缘都弯曲折叠成封闭结构。有序排列的碳层被层错和断点分割成许多微区。在对催化剂研究的基础上,本文认为片状碳纳米带的生长是通过碳原子在片层状催化剂颗粒中的扩散、析出来实现的。碳层从催化剂片层侧面中一层一层地析出,形成带状外观。展开更多
使用较低的快淬速度(V =2 2m·s- 1 ) ,可以使Fe Cu Nb Si B薄带实现淬态纳米晶化。Fe Cu Nb Si B薄带析出αFe(Si)纳米相,其晶粒尺寸在淬态薄带Fe73Cu1 .5Nb3Si1 3.5B9中约为15nm ,在Fe71 .5Cu3Nb3Si1 3.5B9中约为10nm。添加Cu元...使用较低的快淬速度(V =2 2m·s- 1 ) ,可以使Fe Cu Nb Si B薄带实现淬态纳米晶化。Fe Cu Nb Si B薄带析出αFe(Si)纳米相,其晶粒尺寸在淬态薄带Fe73Cu1 .5Nb3Si1 3.5B9中约为15nm ,在Fe71 .5Cu3Nb3Si1 3.5B9中约为10nm。添加Cu元素可以细化淬态薄带的晶粒。实验发现磁阻抗ΔZ/Z0 ,磁电阻ΔR/R0 ,磁电抗ΔX/X0 三条曲线交叉于一点,通过推导发现此现象具有必然性。淬态薄带Fe74 .5-xCuxNb3Si1 3.5B9的磁阻抗显示了较强的Cu含量依赖性。在快淬速度v =2 2m·s- 1 下,在x =1.5和x =3左右观察到磁阻抗峰值现象。展开更多
基金This work was supported by the State Key Project of Fundamental Research for Nanoscience and Nanotechnology （Nos. 2011CB932401, 2011CBA00500, and 2012CB224802）, and the National Natural Science Foundation of China （Nos. 21221062, 21131004, and 21390393）. The authors thank Electron Microscopy Laboratory of Peking University for the help with HRTEM analysis.
文摘Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] direction, and the main exposed facet is the （720） crystal plane. The HUWNRs exhibit good electrochemical performance as an anode material in lithium ion batteries because of their unique structure. It is believed that these unique materials may be applied in many fields.
文摘This paper aims at investigating the resonance frequencies and stability of a long Graphene Nano-Ribbon(GNR)carrying electric current.The governing equation of motion is obtained based on the Euler-Bernoulli beam model along with Hamilton’s principle.The transverse force distribution on the GNR due to the interaction of the electric current with its own magnetic field is determined by the Biot-Savart and Lorentz force laws.Using Galerkin’s method,the governing equation is solved and the effect of current strength and dimensions of the GNR on the stability and resonance frequencies are investigated.
文摘采用热化学气相沉积法(thermal chemical vapor deposition,TCVD)在经过高温氨气处理后的硅基铁纳米薄膜表面实现片状碳纳米带的催化生长。通过场发射扫描电子显微镜(field emission scanning electron microscopy,FESEM)的观察可知,生成的碳材料是一种准二维材料,表面具有垂直于其长度方向的纹理,厚(z方向)约几十纳米,宽(y方向)几百纳米,类似于一种"搓板"状的结构。而其宽度沿着其长度方向则有较大的变化,时宽时窄,没有固定的规律。这种带状碳纳米纤维材料的边缘光滑,比中间略宽,类似于一种镶边结构。通过高分辨透射电子显微镜(high resolution transmission electron microscopy,HRTEM)的观察可知,碳纳米带的碳层沿着垂直于碳纳米带长度的(002)方向有统一的排列,其边缘都弯曲折叠成封闭结构。有序排列的碳层被层错和断点分割成许多微区。在对催化剂研究的基础上,本文认为片状碳纳米带的生长是通过碳原子在片层状催化剂颗粒中的扩散、析出来实现的。碳层从催化剂片层侧面中一层一层地析出,形成带状外观。
文摘使用较低的快淬速度(V =2 2m·s- 1 ) ,可以使Fe Cu Nb Si B薄带实现淬态纳米晶化。Fe Cu Nb Si B薄带析出αFe(Si)纳米相,其晶粒尺寸在淬态薄带Fe73Cu1 .5Nb3Si1 3.5B9中约为15nm ,在Fe71 .5Cu3Nb3Si1 3.5B9中约为10nm。添加Cu元素可以细化淬态薄带的晶粒。实验发现磁阻抗ΔZ/Z0 ,磁电阻ΔR/R0 ,磁电抗ΔX/X0 三条曲线交叉于一点,通过推导发现此现象具有必然性。淬态薄带Fe74 .5-xCuxNb3Si1 3.5B9的磁阻抗显示了较强的Cu含量依赖性。在快淬速度v =2 2m·s- 1 下,在x =1.5和x =3左右观察到磁阻抗峰值现象。
