Papers by Author: Mei Liu

Abstract: In this paper, a variety of methods to prepare nanometer thin films, such as LB film method, self-assembly method, vapor deposition method and oil-water two-phase interface deposition method, are first introduced and compared. Then the self-assembly method is used to prepare the silver liquid-like film for the magnetic fluid deformable mirror. The basic principle of configuration of the silver thin films is discussed and a large area of ordered and close-packed multilayer structures of encapsulated silver nanoparticles is fabricated. The results showed that the film has good reflectivity and stability.

Abstract: Illegal cooked oil is a serious food safety issue in China, while an effective authentication method is still lacking. In this paper, a microfluidic device was applied for the discrimination of low-grade oil from edible oil, by creating water droplets of different sizes in different oils.

Abstract: This paper models the hydrodynamic focusing performance of a micro-fluidic chip with rectangular cross-sections, and the relationships between the aspect ratio, flow rate ratio of sheath flows to the sample flow, and dimensions and position of the focused sample flow are obtained. The simulation results are consistent with theoretical outcomes. And preliminary experiments were carried out to prove the simulation results.

Abstract: This review paper introduces the principles and successful examples of dielectrophoresis (DEP) which was used to position nanowires suspended in fluid medium between two electrodes. The main external affect factors of DEP assembly are discussed in detail, including the potential and frequency of applied electric field, the electrode structure, and the concentration of the nanowire solution.

Abstract: Magnetic fluid based liquid mirrors represent a promising technology. Compared with the conventional solid mirrors, magnetic fluid deformable mirrors (MFDMs) have the advantages of large strokes, low cost and easy scalability. In this paper, the brief history of the development of MFDMs was first introduced, the working principle of MFDMs with fluid mechanics and electromagnetic field was presented next and then the advantages of MFDMs as well as their challenges are discussed.

Abstract: Recently, magnetic fluid deformable mirrors (MFDMs) were proposed as a novel type of wavefront correctors for adaptice optics (AO) systems, which offer cost and performance advantages over existing wavefront correctors. These mirrors are developed by coating the free surface of a magnetic fluid with a thin reflective film of nano-particles. The reflective surface of the mirrors can be deformed using a locally applied magnetic field and thus serves as a wavefront corrector. In this paper, the working principle of MFDMs is first presented, then the perspectives of MFDMs that will have to be addressed before they can be finally used practically in AO applications are discussed.

Abstract: Efficient assembly of nanowires or nanotubes into functional nanodevices is one of the keys for practical application of the promising nanotechnology. Generally there are two ways for the assembly of nanowires or nanotubes: directed assembly during growth and post-growth assembly. The post-growth assembly technique is advantageous in some aspects comparatively for it puts little limitation on the nanowire or nanotube materials involved, and it can produce large nanowire arrays with better consistency. So this paper reviewed post-growth nanowire assembly techniques and discussed their advantages and shortcomings.

Abstract: Efficient integration of synthetic nanotubes/nanowires into functional nanodevices by bottom-up approaches is the key of mass production of nanodevices, and is still a big challenge. Here we present a simple microfluidic method of patterning and aligning a large scale of carbon nanotubes by hydrodynamic focusing: the sample solution carrying carbon nanotubes were hydrodynamically controlled by the sheath flows. This method can be used to align and position both a large scale of nanotubes and a few lines of nanotubes to designated positions, offering a general pathway for assembly of nanosystems.

Abstract: The extended nonholonomic double integrator (ENDI) cannot be asymptotically stabilized by a continuous and time-invariant feedback controller since it violates the Brockett’s condition. In this paper, a new continuous control scheme is proposed to stabilize the ENDI system without drift. The dynamics of an ENDI system is enlarged to a higher dimensional space where a continuous but time-varying control law is designed for its stabilization. Besides the theoretical proofs, simulations conducted on the dynamics of a mobile robot are also presented to demonstrate the validity and performance of the proposed method.

Abstract: The extended nonholonomic double integrator (ENDI) cannot be asymptotically stabilized by a continuous and time-invariant feedback controller since it violates the Brockett’s condition. In this paper, a new continuous control scheme is proposed to stabilize the ENDI system without drift. The dynamics of an ENDI system is enlarged to a higher dimensional space where a continuous but time-varying control law is designed for its stabilization. Besides the theoretical proofs, simulations conducted on the dynamics of a mobile robot are also presented to demonstrate the validity and performance of the proposed method.