Hao Lv

Two dimensional MoS2/CNT hybrid ink for paper-based capacitive energy storage

Developing two dimensional (2D) materials based ink is an advanced method for fabricating printable and flexible electronic devices. 2D few-layered molybdenum disulfide (MoS2) reveals a great potential for capacitive energy storage because of its layered structure (for ion intercalation), high surface area (provide active sites) and multi-valence state of Mo (introduce pseudocapacitive reactions). These unique properties could intensively improve the potential of MoS2 for supercapacitors. However, MoS2 is a semiconductor with low conductivity, which limits its performance in electrochemistry. In the meantime, MoS2 based ink for flexible energy storage application has been barely investigated. In this work, we design a MoS2 and carbon nanotube (MoS2/CNT) hybrid ink that uses exfoliated MoS2 nanosheet and CNT to fabricate a paper-based supercapacitor. A strong synergistic effect between MoS2 and CNT in capacitive performance was observed due to the good conductivity of CNT and high capacitance of MoS2. Paper-based solid-state device is also fabricated which reveals good flexibility and high capacitive performance. This hybrid ink represents a new road for flexible paper-based devices.

Generation of vector beams based on dielectric metasurfaces

Vector beam has recently attracted many attentions due to novel properties and wide applications. Finding a method efficiently generating high quality vector beam is very important when it is used in practice. In this paper, we theoretically and experimentally demonstrate the generation of vector beams based on dielectric metasurfaces, which are fabricated by femtosecond laser writing in silica glass. Three types of linearly polarized vector beams are produced by three specially designed metasurfaces. The vector beam generator is convenient and robust due to its simple optical path. We believe that metasurfaces will be widely applied in manipulating polarization, phase, and amplitude of light as the development of fabrication technology.

Numerical analysis of low chromatic aberration of a gradient refractive index rod lens

The oxide compositions (OCs) model is established for discussing the chromatic aberrations of a gradient refractive index rod lens. The chromatic aberrations for Na(+)/Li(+), K(+)/Cs(+), and K(+)/Tl(+) ion exchanges are discussed based on the OC model and the Huggins-Sun-Davis (HSD) model. Theoretical results indicate that the function value mainly depends on base glass properties and the nature of exchanging ion pairs, and rarely depends on the quantity of ion exchange. Experimental results show that the chromatic aberrations using the OC model have smaller errors than with the HSD model. The estimating average errors between the OC model and the HSD model are -0.051, -0.0067, and 0.0047 for the K(+)/Tl(+), Li(+)/Na(+), and K(+)/Cs(+) ion exchanges, respectively.

Fabrication of Glass Microspheres Using the Powders Floating Method

Glass microspheres are fabricated using the powders floating method and characterized by differential thermal analysis (DTA) �I X-ray diffraction (XRD) and scanning electron microscope (SEM). Research results indicate that the optimal annealing temperature of glass microspheres is 590�� , glass microspheres have better surface qualities and can be used in many field. Keywords-glass microspheres, powders floating method, surface qualities

Coupling efficiency of optical coherence tomography system with gradient refractive index rod lens as reference arm

The coupling efficiency equation of an optical coherence tomography system with a gradient refractive index rod lens as the reference arm is established and discussed theoretically and experimentally. The experimental result is consistent with the theoretical result. The higher coupling efficiency of the OCT system can be obtained if θ, which is the angle between the mirror and the y axis, is smaller than 0.5°.

Research on the Characteristics of Compound Cavity Semiconductor Laser with Narrow Linewidth

In this paper, a new type compound cavity semiconductor laser is designed and the several important parameters, such as threshold gain, coupling efficiency, surface reflectivity and composite cavity length, are discussed. Research results indicate the narrow linewidth semiconductor laser compound cavity can be achieved narrow linewidth 10-4.

Finite Schematic Eye Model with Maxwell Fish-Eye Spherical Lens

In this paper, the finite schematic eye model with Maxwell fish-eye spherical lens is proposed. Spherical aberration, sagittal and tangential power errors, astigmatism, field curvature and internal and external angles of the pupil ray are compared with four existing model eyes and real eye. The finite schematic eye model with Maxwell fish-eye spherical lens provides excellent estimation of spherical aberration and field curvature and has reasonable estimations of sagittal and tangential power errors and astigmatism.

Performances Comparison of Ball Lenses Having Gradient Refractive Index Distribution and Homogeneous Medium

Gradient refractive index(GRIN) ball lenses are novel optical devices and can be used to couple light between laser diode and optical fiber. Moreover, as they can be very small as less than 3mm, they may help to improve optical device compactness. This paper compares the performances of ball lenses having gradient refractive index distribution and homogeneous medium. It appears that the performances of gradient refractive index ball lenses are better than them of homogeneous ball lenses.

Fabrication and adsorption characterizations of porous glass ceramic microspheres

A method to fabricate the porous glass ceramic microspheres is reported. The fabricated glass microspheres and the porous glass ceramic microspheres are characterized by scanning electroscopy (SEM) and transmission electron microscopy (TEM), respectively. The sizes of glass microspheres and the pore diameters of the porous glass ceramic microspheres are estimated, respectively. The adsorption properties of the porous glass ceramic microspheres are characterized by adsorption isotherm, surface area and pore distribution with the help of N2 adsorption. The adsorption isotherms of phenol based on which effective means to increase the adsorption of porous glass ceramic microsphere are tested.

Fabrication and Optical Characterization of Silica Microspheres Having Europium Ions

In this paper, the silica microspheres having europium ions are fabricated using the powders floating method. The optical characterizations of the silica microspheres having europium ions are performed in the attenuated-total-reflection configuration under excitation of 395nm laser. When the diameters of the silica microspheres having europium ions are 60�� m and 90�� m , the estimated quality factors of whispering gallery modes are 2100 and 2400 respectively.