Solid State Phenomena Vols. 121-123

Abstract: Nano drive parts based on thermal deformation is a new drive method, it can afford more than 5000N feeding force, but it has great time-lag change which make it very difficult to control, so it is critical to choose control method. In order to apply monodrome modal algorithm control (MMAC) to nano feed system having large time-lag, A new step by step fitting method by the experimental results to confirm model parameters of control system was presented, and the characteristics of control system was analyzed. Simulation results show that there is periodic error generated by model building, when the number of terms (N) adopted in predicative modal of non-parametric and monotonic is lesser, i.e. little N generated periodic error and there is a lager error when the sampling point are near N
2N
3N, but with the increasing of number of terms (N), error becomes little, so comprehensive information and error depend on the number of term (N). Predicative step is related to response speed and robust characteristic, there are longer response speed and better robust characteristic, when the predicative step is added. 15nm feeding accuracy was achieved by experiments, when the MMAC was used in nano drive parts having large time-lag change.

Abstract: TiO2 photocatalyst has attracted much attention in recovering valuable metal ions from industrial wastewater because TiO2 shows chemical stability and good wear resistant, and a photocatalytic reaction occurs by illumination of the sun or fluorescent light. In this study, Au removal and recovery in a gilding wastewater using TiO2 photocatalyst was evaluated. Commercially obtained TiO2 powder and TiO2 film prepared by spray and screen print method were used for Au adsorption. The cyanide existed in a plating wastewater was firstly removed with peroxide or persulfate because a driving force for Au ion reduction during photocatalytic process could decrease by the existed cyanide. Compared with persulfate, peroxide shows relatively slow removal rate of cyanide but no precipitation occurs. With respect to photocatalytic reaction of TiO2 powder and film for Au removal and recovery, it was found that the addition of 10 vol% of methanol as a hole scavenger increases the rates of Au ion reduction and Au adsorption on the TiO2 powder and film, subsequently the reaction of Au photoadsorption was completed within 60 min. Au lumps on the TiO2 particles obtained by photocatalytic reduction of TiO2 was confirmed by XRD analysis and TEM observation.

Abstract: WC-10Co nanocomposite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing (HIP). Influences of ball-milled time on properties and microstructure of ultrafine WC-10Co cemented carbide were investigated. The results show that ultrafine WC-10Co cemented carbides can reach 99.79% relative density, and transverse rupture strength is more than 3750MPa, Rockwell A hardness is more than 92.6, the average grain size is less than 440 nm, when ball-milled time is 48 hours, ultrafine WC-10Co cemented carbide with excellent properties and fine microstructure is obtained. The optimum ball-milling time is 48 hours.

Abstract: The characters of metal oxide gas sensing nano-thin films are studied. The formula of the dynamical thickness effect characteristic time is given. The relation of the sensitivity Sn and the film thickness l, the character of existing the optimum thickness, the character of the change of conductance activity energy with the film thickness are given also. The idea of diffusion reaction of gas sensing mechanism and the idea of mesoscopic effect in the nano-thin films are proposed.

Abstract: The social dimensions of nanotechnology have aroused widespread interests in recent years. In US, for example, the National Nanotechnology Initiative (NNI) mandates that a large amount of funding resources to be allocated for studying the societal implications of nanotechnology. Since NNI took effect in 2001, teaching and research in the social dimensions of nanotechnology have grown tremendously [1]. Advances in social network analysis have opened up new research opportunities to understand nanotechnology research and development. In particular, understanding scientific collaboration can help researchers and entrepreneurs better strategize and exploit research opportunities in nanotechnology. Moreover, social network analysis relies heavily on quantitative measures. This feature may serve as a bridge between natural and social scientists to jointly investigate the future directions of nanotechnology research and development (R&D). Using a social network analysis framework, this paper examines the patterns of intra- and inter-disciplinary collaborations among nanotechnology scientists. As an exploratory study, I discuss three methodological issues after reporting some descriptive results. First, the collaborative density used in this study is only one structural measure among many others. When investigating network positions, researchers can utilize other network measures according to specific purposes. Second, generalization may be methodologically problematic for network data. Accordingly, researchers should ascertain the plausibility of probability assumptions. Finally, Bayesian estimates allow researchers to combine beliefs about prior distribution and sample likelihood. Assuming a beta-binomial model, I present a set of Bayesian estimates.

Abstract: This paper proposes a novel microfluidic system for cell/microparticle recognition and manipulation utilizing digital image processing technique (DIP) and optical tweezer under microfluidic configuration. Digital image processing technique is used to count and recognize the cell/particle samples and then sends a control signal to generate a laser pulse to manipulate the target cell/particle optically. The optical tweezer system is capable of catching, moving and switching the target cells at the downstream of the microchannel. The trapping force of the optical tweezer is also demonstrated utilizing Stocks-drag method and electroosmotic flow. The proposed system provides a simple but high-performance solution for microparticle manipulation in a microfluidic device.

Abstract: In the present work, we aimed to investigate the immobilization of Bovine Serum Albumin (BSA) into poly (vinyl alcohol) (PVA) network. PVA hydrogels with BSA were characterized by Synchrotron SAXS radiation associated with Fourier Transform Infrared Spectroscopy (FTIR). We synthesized hydrogels by dissolving PVA in aqueous solution (5.0 wt%) and crosslinked with glutaraldehyde (GA). PVA and PVA/GA hydrogels samples were immersed in BSA aqueous solution for protein immobilization. FTIR spectra showed major vibration bands associated with PVA and GA chemical groups, and BSA protein amides. Regarding to SAXS characterization, the slope of the log I(q), scattering intensity, as a function of log q, the scattering vector, provided important information about the morphology of entities present in the system. Two different scattering patterns were obtained for PVA (slope = 3.5) and PVA/BSA (slope=1.5 and 3.0). These results have given strong evidence of nano-ordered dispersed globular BSA immobilized into chemically crosslinked PVA hydrogel network. SAXS analyses have indicated that the scattering q-vector maximum value was shifted by altering PVA polymer hydrogel with GA crosslinker and also with BSA incorporation into the network.

Abstract: Linear encoders for nanoscale position sensing based on vertical arrays of single multi-walled carbon nanotubes (MWNTs) are investigated from experimental, theoretical, and design perspectives. Vertically aligned single MWNTs are realized using a combination of e-beam lithography and plasma-enhanced chemical vapor deposition (PECVD) growth. Field emission properties of the array are investigated inside a scanning electron microscope (SEM) equipped with a 3-DOF nanorobotic manipulator with nanometer resolution functioning as a scanning anode. Lateral position of the scanning anode is sensed from the emission distribution. High resolution (best: 12.9 nm; practical: 38.0 nm) for lateral position sensing around an emitter has been realized.

Abstract: The third-order nonlinearities of PbS nano-dot and nano-belts have been investigated using the Z-Scan technique with nanosecond laser pulses at 532nm. The effect of the PbS semiconductor nanometer-size and spatial forms on the third-order optical nonlinearities and optical limiting properties would be discussed when the nanometer-size were larger than the exciton size. The optical limiting mechanism of materials was discussed in the nanosecond time domain.