Advanced Materials Research Vols. 403-408

Abstract: It introduced the basic principle of measuring the size of nanoparticles by the method of Photon Cross-Correlation spectroscopy (PCCS). The measuring time for Au particle size measurement at different concentration using PCCS was studied. We measured gold particles with an average diameter of 24.5 nm at different concentration and different measuring times by PCCS. The measuring results demonstrate that for the same measuring time, the higher the concentration is, the smaller the standard deviation of repeated measurements is; for suspension of the same concentration, the longer the measuring time is, the smaller the standard deviation of repeated measurements is. It fitted the relationship between the standard deviation of measuring results and the measuring time at difference concentration. For the needed measuring accuracy, we can get the measuring time for some concentration according to the curve fitting.

Abstract: Thin CuInSi nanocomposite films were prepared by magnetron co-sputtering. The structures of CuInSi nanocomposite films were detected by X-ray diffraction(XRD); XRD studies of the annealed films indicate the presence of CuInSi, the main crystal phase peak is at 2θ=42.400°. The transmittance (T) spectra of the films were measured by Shimadzu UV-2450 double beam spectrophotometer. The band gap has been estimated from the optical absorption studies and found to be about 1.40 eV, but changes with purity of CuInSi.

Abstract: Thin Nano-CuInSi films have been prepared by multilayer synthesized method using magnetron sputtering technology, and followed by annealing in N2 atmosphere at different temperatures. The structures of CuInSi films were detected by X-ray diffraction(XRD); X-ray diffraction studies of the annealed films indicate the presence of CuInSi, the peak of main crystal phase is at 2θ=42.450°; the morphology of the film surface was studied by SEM. The SEM images show that the crystalline of the film prepared by multilayer synthesized method was granulated. The transmittance (T) spectra of the films were measured by Shimadzu UV-2450 double beam spectrophotometer. The calculated absorption coefficient is larger than 105 cm−1 when the wavelength is shorter than 750 nm. The band gap has been estimated from the optical absorption studies and found to be about 1.47 eV, but changes with purity of CuInSi. CuInSi thin film is a potential absorber layer material applied in solar cells and photoelectric automatic control.

Abstract: An effective method was used to bond carbon nanotubes onto metal electrodes by induction heating process. A good contact between carbon nanotubes and metal electrodes was formed. The contact resistance can be reduced to approximate 95% after induction heating process. Because the induction heating process will selective occur on the structures with high relative permeability and low electrical resistivity, this method could be utilized to realize large scale localized bonding.

Abstract: Recently carbon nanotubes (CNTs) are reported to be able to generate large magnetic field because of their nanometer-size-diameter[2]. The magnetic fields around CNTs current path are investigated by magnetic force microscopy (MFM). Under the consideration of the magnetic properties of magnetically coated tip of MFM, tip heights, current directions, and background magnetic field, etc., the magnetic field distribution are analyzed. The distribution of the magnetic field generated by the CNTs current is found to be asymmetric, and its distribution anomaly is found to be a kind of hysteresis effect of the MFM cantilever materials.

Abstract: In this article, silicone pressure sensitive adhesives (PSAs) were modified with the Nano-SiO₂ and nano-Al₂O₃. In order to prevent agglomerate, nano powder was dealt with silane coupling agent and then mixed into PSAs, both of the processes were under the action of ultrasonic. The results of test showed that all kinds of temperature index of modified PSAs were increased obviously, which means the high heat resistance of PSAs increased evidently. At the same time, its peel strength also increased, but the tack decreased. The effects of different nano powder are different, and the decomposition temperature of the nanocomposite raised 8.32% when the content of nano-SiO₂ is 4.5wt%, while raised 14.02% when that of nano-Al2O3 is 1.5wt%, and the best compositive performances were obtained at this content of Nano-Al₂O₃.

Abstract: Lithium is widely used in the pharmaceutical industry, fuel cell, ceramic industry, glass, lubricants, aluminum industry, refrigerant, nuclear industry and photovoltaic industry. The thermal properties of lithium are very important for the design and safe operation. The MEAM potential was applied to calculate thermal conductivity of lithium with emphasis on size effect analysis in the lithium nanometer film using non-equilibrium molecular dynamics simulation method. The results show that the lithium thermal conductivity increases with increasing film thickness. The obvious size effect and anisotropy of thermal conductivity are found in the lithium nanometer film. From the simulation results, the difference of normal and tangential thermal conductivity has been analyzed quantitatively.

Abstract: The objective is to demonstrate that physical properties of multifunctional material systems can be tailored for specific applications by controlling different types of nanotubes, their concentration and degree of alignment. The properties of structured polymers can be enhanced by combining nano tubes with desired properties to form a nano polymer. These may have the potential to provide structural integrity as well as sensing and/or actuation capabilities. By proper selection of the polymer matrix to promote donor acception and/or dispersion interactions can improve adhesion at the interface between the nano- tubes and hence also the polymer matrix significantly. An effective sensor material that responds to strain, stress, pressure, and temperature can be yielded by using very small loadings of single wall nanotubes in a polyimide matrix. These materials also exhibit significant actuation in response to applied electric fields. Alternative thermodynamic routes involve enhancing polymer/SWCNT interactions via amphiphilic surfactants, hydrophobic interaction with nanotubes, physical wrapping with conjugated polymers which exhibit enhanced dispersion interactions by adopting a π-stacked geometry , donor-acceptor interactions via charge transfer , Zwitterion complex formation , and non-specific interactions using DNA or peptide sequence.

Abstract: In nano manipulation, carbon nanotubes (CNT) mounted on the AFM tip was used for pick and place of the nano size objects. In releasing step, the van der Waals adhesive force among the object and the contact surfaces of the gripper is not still well understood. In this paper, the adhesive electrostatic force, van der Waals (VDW) force between two cantilever tips and VDW force among cantilevers and the object are considered as dominant forces to pick and place the nano object. The equations governed on nanotweezer are solved using FEM code. The effect of object size, gap size and tips length on pull-in voltage are evaluated. The presented model could be used to design the tweezers for pick and place of size-defined nano object mounted on microgripper.

Abstract: The electronic transport properties are the basis for investigations on silicon carbide nanotube (SiCNT), which are suitable to develop novel nanometer electronic devices. The electronic transport properties of Single-Walled (8, 0) SiCNTs with antisite defects are investigated with the method combined Non-Equilibrium Green’s function with density functional theory. Results show that the similarity on electronic transport properties of the nanotube with different defects is high. Under a bias value greater than 1.0 V, a nearly exponential relationship between the bias and the current is achieved, which originates from more orbital participating in its transport properties caused by the increase of the bias.