Single Nano Research Articles

Origin of magnetic and dielectric response in single phase nano crystalline BiFeO3

Stoichiometric and single phase synthesis of BiFeO3 is critical both in its particle industrial applications as well as in understanding the origin of its attractive dielectric and magnetic properties. In this study, BiFeO3 has been obtained at temperatures as low as 400 °C. Zero Fe+2/Fe+3 ratio, and absence of bismuth and oxygen non-stoichiometry have been probed by 57Fe Mössbauer spectroscopy. The appearance of different magnetic phases in 57Fe Mössbauer spectrum, MH hysteresis curve and exchange bias effect have been conferred on the basis of magneto-crystalline anisotropy and particle size distribution. Dependence of the dielectric response on the applied electric field reveals that the colossal dielectric response in BiFeO3 is dominated by extrinsic effects at grain-grain interface.

Near-field optical mapping of single gold nano particles using photo-induced polymer movement of azo-polymers

In this study, polymer movement was induced in azo-polymer films by optical near-fields generated in the vicinity of single gold nano particles (GNPs) to visualize near-field distribution with a spatial resolution beyond the diffraction limit of light. A linearly polarized (Ex) laser beam was irradiated into GNPs to excite local surface plasmon resonance that enhanced the near-field around the GNPs. The findings indicated that different GNP diameters (that is, 50nm and 80nm) resulted in different deformation patterns on the films. The results were compared with theoretical calculations of near-field distributions, and the observations revealed that the deformation patterns were dependent on the ratio between Ex and Ey wherein each possessed a different field distribution.

Fabrication and effect study of microfluidic SERS chip with integrated surface liquid core optical waveguide modified with nano gold

A novel microfluidic chip with integrated Teflon AF1600 surface liquid core optical waveguide (LCW) modified with nano gold was proposed and fabricated in this article. Physical deposite method was used to integrate Teflon AF1600 LCW into microchannel. After that, the inner surface of Teflon AF1600 LCW was chemically modified at temperature of 40 °C, subsequent nano gold were in situ immobilied on the silanized inner surface of Teflon AF LCW precoated with a thin layer of poly(diallyldimethylammonium chloride) within microchannel by a chemical self-assembly method. Under the optimized conditions, the prepared microfluidic SERS chip exhibited high sensitivity for R6G with detection limit of 10−11 mol/L and SERS enhancement factor (EF) of 2.7 × 108. Compared to single nano gold SERS enhancement substrate within a microfluidic chip, the SERS detection sensitivity for R6G was improved 4 orders of magnitude. Apart from high SERS enhancement effect, the as-prepared integrated microstructure had extremely good SERS detection reproducibility and duration stability. Furthermore, it was successfully used to detect the bovine serum albumin (BSA), and exhibited excellent SERS response. The research showed great prospects and technical support for design and fabrication of integrated SERS microfluidic chip and sensitive detection of trace biochemical samples.

A method for high precision sequencing of near full-length 16S rRNA genes on an Illumina MiSeq.

BackgroundThe bacterial 16S rRNA gene has historically been used in defining bacterial taxonomy and phylogeny. However, there are currently no high-throughput methods to sequence full-length 16S rRNA genes present in a sample with precision.ResultsWe describe a method for sequencing near full-length 16S rRNA gene amplicons using the high throughput Illumina MiSeq platform and test it using DNA from human skin swab samples. Proof of principle of the approach is demonstrated, with the generation of 1,604 sequences greater than 1,300 nt from a single Nano MiSeq run, with accuracy estimated to be 100-fold higher than standard Illumina reads. The reads were chimera filtered using information from a single molecule dual tagging scheme that boosts the signal available for chimera detection.ConclusionsThis method could be scaled up to generate many thousands of sequences per MiSeq run and could be applied to other sequencing platforms. This has great potential for populating databases with high quality, near full-length 16S rRNA gene sequences from under-represented taxa and environments and facilitates analyses of microbial communities at higher resolution.

Controllable preparation of copper phthalocyanine single crystal nano column and its chlorine gas sensing properties

The unsubstituted copper phthalocyanine (CuPc) single crystal nano columns were fabricated for the first time as chlorine (Cl2) gas sensors in this paper. The nano columns of CuPc have been prepared on different substrates via template-free physical vapor deposition (PVD) approach. The growth mechanism of CuPc nano column on quartz was explored and the same condition used on other substrates including glass, sapphire (C-plane<0001>, M-plane<101¯0>, R-plane<11¯02>), Si and SiO2/Si came to a same conclusion, which confirmed that the aligned growth of CuPc nano column is not substrate-dependent. And then the CuPc nano column with special morphology was integrated as in-situ sensor device which exhibits high sensitivity and selectivity towards Cl2 at room temperature with a minimum detection limit as low as 0.08 ppm. The response of sensor was found to increase linearly (26∼659%) with the increase for Cl2 within concentration range (0.08∼4.0ppm). These results clearly demonstrate the great potential of the nano column growth and device integration approach for sensor device.

Measuring anti-bunching Effect from Single Dye Molecules and Single Quantum Dots

Antibunching is a quantum effect demonstrating clearly the quantum nature of the radiation field. Its detection through measurements of the second order correlation function is a direct proof of the presence of single molecule or single nano particle. In this paper we present the experimental setup of the Hanbury Brown - Twiss interferometer and the measurement results of the antibunching effect from single Rhodamine B dye molecules and single CdTe quantum dots in dilute solution. By fitting the second order correlation data, we derive a fluorescence lifetime of approximately 2 ns for Rhodamine B and 45 ns for CdTe quantum dots. Our results demonstrate an alternative way for determining the fluorescence lifetime using the antibunching effect.

Pullout strength of graphene and carbon nanotube/epoxy composites

An atomistic multiscale modelling approach is used to simulate the nonlinear pullout behaviour of interlinked single walled carbon nano tubes (SWCNT) and single layer graphene sheets (SLGS) embedded in an epoxy polymer. The pullout forces have been computed for various configurations of nanocomposites (SWCNT-SWCNT, SLGS-SLGS and hybrid SLGS-SWCNT), also by evaluating the effect provided by three different interlink compounds. The interfacial strength due to fibre pullout predicted by the hybrid atomistic-FE model is compared against experimental and molecular dynamics results available in open literature. The results show the specific deformation characteristics (localised auxetics) that provide an increase of pullout forces and interfacial strength with the use of the links.

Bifurcation and pull-in voltages of primary resonance of electrostatically actuated SWCNT cantilevers to include van der Waals effect

In this work the voltage response of primary resonance of electrostatically actuated single wall carbon nano tubes (SWCNT) cantilevers over a parallel ground plate is investigated. Three forces act on the SWCNT cantilever, namely electrostatic, van der Waals and damping. While the damping is linear, the electrostatic and van der Waals forces are nonlinear. Moreover, the electrostatic force is also parametric since it is given by AC voltage. Under these forces the dynamics of the SWCNT is nonlinear parametric. The van der Waals force is significant for values less than 50 nm of the gap between the SWCNT and the ground substrate. Reduced order model method (ROM) is used to investigate the system under soft excitation and weak nonlinearities. The voltage-amplitude response and influences of parameters are reported for primary resonance (AC near half natural frequency).

The Effect of Pores in Dual Nano Hydroxyapatite Coating on Thermally Oxidized Commercial Pure Titanium : Mechanical and Histological Evaluation

Background:In this study,TiO2 layer was thermally grown as a diffusion barrier on CP Ti substrate prior to electrophoretic deposition of HA coatings, to improve the coating’s compatibility also macro and micro pores in nano Hydroxyapatite dual coatings were created and their effect on the bond strength between the bone and implant was evaluated. Materials and methods: Electrophoretic Deposition technique (EPD) was used to obtain coatings for each one of four types of Hydroxyapatite(HA)on CP Ti screws (micro HA, nano HA, dual nano HA with micro pores, dual nano HA with macro pores) where carbon particles used as fugitive material to be removed by thermal treatment to create porosity.For examination of the changes occurred on the substrate, SEM, SPM and XRD used, coatings characterized by XRD, SEM and interfacial shear strength measurements. Results:The results mentioned the formation of rutilenano TiO2 with, SEM showed that the size of pores in HA coatings corresponded to the size of carbon particles. Statistical analysis of the removal torque tests showed highest means of the single nano HA coating at 2 and 4 weeks implantation intervals. Histological analysisrevealed a faster reaction of bone and higher osteoblasts activity towards thermally oxidized CP Ti implants coated with single nano HA coating. Conclusion:Carbon particles as a fugitive material within nano HA coat produced porosity.Presence of pores ˃ 1µ in nano HA coats did not achieve highest removal torque values nor highest osteoblasts activity in 2 and 4 weeks implantation intervals. Keywords:Titanium, Thermal oxidization, Nano Hydroxyapatite, Coatings, porosity.

Decoupling of constitutive equations for multi-layered nano-plates embedded in elastic matrix based on non-local elasticity theory using first and higher-order shear deformation theories

The constitutive equations of nano-plates embedded in elastic matrix are derived based on Eringen non-local elasticity theory. Considering the non-local differential constitutive relations of Eringen theory in Cartesian and cylindrical coordinates system based on the first and higher order shear deformation theories and using the Von Karman strain field, the equilibrium differential equations are derived in terms of generalized displacements and rotations. In addition, the obtained governing equations for single layer nano plates are developed for multi-layer nano-plates. Rectangular, annular/circular and sectorial nano-plates are considered. In the most of the investigations in non-local elasticity theory, the classical plate theory (CLPT) is used, however in this paper, the governing equations are derived based on both FSDT and HSDT theories because of obtaining more accurate results.

Multiple structure single parameter: analysis of a single protein nano environment descriptor characterizing a shared loci on structurally aligned proteins.

A graphical representation of physicochemical and structural descriptors attributed to amino acid residues occupying the same topological position in different, structurally aligned proteins can provide a more intuitive way to associate possible functional implications to identified variations in structural characteristics. This could be achieved by observing selected characteristics of amino acids and of their corresponding nano environments, described by the numerical value of matching descriptor. For this purpose, a web-based tool called multiple structure single parameter (MSSP) was developed and here presented. MSSP produces a two-dimensional plot of a single protein descriptor for a number of structurally aligned protein chains. From a total of 150 protein descriptors available in MSSP, selected of >1500 parameters stored in the STING database, it is possible to create easily readable and highly informative XY-plots, where X-axis contains the amino acid position in the multiple structural alignment, and Y-axis contains the descriptor's numerical values for each aligned structure. To illustrate one of possible MSSP contributions to the investigation of changes in physicochemical and structural properties of mutants, comparing them with the cognate wild-type structure, the oncogenic mutation of M918T in RET kinase is presented. The comparative analysis of wild-type and mutant structures shows great changes in their electrostatic potential. These variations are easily depicted at the MSSP-generated XY-plot. The web server is freely available at http://www.cbi.cnptia.embrapa.br/SMS/STINGm/MPA/index.html Web server implemented in Perl, Java and JavaScript and JMol or Protein Viewer as structure visualizers. goran.neshich@embrapa.br or gneshich@gmail.com Supplementary data are available at Bioinformatics online.

Buckling of hybrid nanocomposites with embedded graphene and carbon nanotubes

With the aid of atomistic multiscale modelling and analytical approaches, buckling strength has been determined for carbon nanofibres/epoxy composite systems. Various nanofibres configurations considered are single walled carbon nano tube (SWCNT) and single layer graphene sheet (SLGS) and SLGS/SWCNT hybrid systems. Computationally, both eigen-value and non-linear large deformation-based methods have been employed to calculate the buckling strength. The non-linear computational model generated here takes into account of complex features such as debonding between polymer and filler (delamination under compression), nonlinearity in the polymer, strain-based damage criteria for the matrix, contact between fillers and interlocking of distorted filler surfaces with polymer. The effect of bridging nanofibres with an interlinking compound on the buckling strength of nano-composites has also been presented here. Computed enhancement in buckling strength of the polymer system due to nano reinforcement is found to be in the range of experimental and molecular dynamics based results available in open literature. The findings of this work indicate that carbon based nanofillers enhance the buckling strength of host polymers through various local failure mechanisms.

Design of NEMS Based Intraocular Pressure Sensing System

Glaucoma is one of the leading causes of irreversible blindness. The change in intraocular pressure (IOP) inside the anterior chamber of the eye beyond its normal limit leads to this condition which initially affects the peripheral vision and if left untreated, results in permanent blindness. Early detection of elevation in IOP helps to slow down the disease progress. Thus a highly precise, cost effective, miniaturized pressure sensor is an important need for sensing the IOP. In the present work, the piezoresistivity of Single Walled Carbon Nano Tubes (SWCNT) is exploited to design a diaphragm based Nano-Electro-Mechanical Systems (NEMS) pressure sensor. Finite Element Method simulation is then performed to find the change in resistance ofthe piezoresistive material. This change in resistance results a change in output voltage corresponding to the pressure applied, which can be measured by an interfacing circuitry consisting of a low voltage amplifier andlow power-high speed Analog to Digital Converter (ADC). The resultant pressure sensor response is found to be highly linear and its sensitivity can be increased by changing diaphragm dimensions.

Single layer nano graphene platelets derived from graphite nanofibres.

Solutions of calibrated nanographenides (negatively charged nanographenes) are obtained by dissolution of graphite nanofibre intercalation compounds (GNFICs). Deposits show homogeneous unfolded nanographene platelets of 1 to 2 layers thickness and 10 nm lateral size, evidenced by atomic force microscopy and Raman spectroscopy. Upon oxidation, nanographenide solutions exhibit strong photoluminescence.

レーザアシストを用いたナノセンサの高速細胞インジェクション

Rapid and effective injection of functional nano sensor into a specific living cell with high cell viability is one of the most important issues for single cell analysis. This paper reports a novel method of injecting single magnetic nano sensor into a living MDCK cell using a continuous-wave near infrared laser. The amino-modified polystyrene bead containing magnetic particle was died by FITC as pH indicator. Irradiation of near infrared laser to nano sensor on the cell membrane induces the insertion of the sensor into cell cytoplasm through cell membrane. Experimental results demonstrated the successful injection of magnetic nano sensor into living cells with high injection rates reaching 100 %, cell survival rates of 90 % at 14 mW laser power. Injection times was achieved about 1.4 sec.

Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch using electron beam lithography with chemically amplified resist process: III. Post exposure baking on quartz substrates

Electron beam (EB) lithography is a key technology for the fabrication of photomasks for ArF immersion and extreme ultraviolet (EUV) lithography and molds for nanoimprint lithography. In this study, the temporal change in the chemical gradient of line-and-space patterns with a 7 nm quarter-pitch (7 nm space width and 21 nm line width) was calculated until it became constant, independently of postexposure baking (PEB) time, to clarify the feasibility of single nano patterning on quartz substrates using EB lithography with chemically amplified resist processes. When the quencher diffusion constant is the same as the acid diffusion constant, the maximum chemical gradient of the line-and-space pattern with a 7 nm quarter-pitch did not differ much from that with a 14 nm half-pitch under the condition described above. Also, from the viewpoint of process control, a low quencher diffusion constant is considered to be preferable for the fabrication of line-and-space patterns with a 7 nm quarter-pitch on quartz substrates.

Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch using electron beam lithography with chemically amplified resist processes: II. Stochastic effects

Electron beam (EB) lithography is a core technology for nanofabrication. Owing to the increasing demand for high-resolution semiconductor lithography, the requirements for the resist processes of EB lithography for the photomasks used in ArF immersion and extreme ultraviolet lithographies and the mold fabrication of nanoimprints have also become stricter. In this study, the feasibility of single nano patterning by EB lithography with a chemically amplified resist process was investigated from the viewpoint of stochastic effects. The latent images of line-and-space patterns with a 7 nm quarter-pitch (7 nm space width and 21 nm line width) were calculated using a Monte Carlo method on the basis of the sensitization and reaction mechanisms of chemically amplified EB resists. Compared with the line-and-space pattern with a 7 nm half-pitch, line edge roughness (LER) and the stochastic pinching generation are considered to be significantly improved by increasing the pitch. It was found that the suppression of the stochastic generation of bridges is the critical issue in 7 nm quarter-pitch fabrication.

3D FEM analyses of the ultrasonic transducer for controlled nanowire rotary driving

Controlled rotary driving of single nano objects is an important technology in the assembling of nano structures, handling of biological samples, nano measurement, etc. However, there have been little analyses on the ultrasonic transducers for the nano rotary driving, which makes the transducer’s optimization impossible. In this work, vibration characteristics of the ultrasonic transducer for rotary driving of single nanowires, which has been proposed by the authors’ group, are analyzed by the 3D finite element method (FEM), and some useful guidelines for designing the transducer are achieved. It is found that the working point still exists when the commonly used metal materials in ultrasonic transducers are used as the vibration transmission strip, and when the vibration transmission strip’s size changes. It is also found that the direction of the elliptical motion of the micro manipulating probe’s tip may be reversed by changing the size of the vibration transmission strip properly. In addition, to ensure the performance consistency of the device, the micro manipulating probe’s length Lm or driving frequency should be designed to avoid the resonance of the micro manipulating probe.

Observation of terahertz-radiation-induced ionization in a single nano island.

Terahertz (THz) electromagnetic wave has been widely used as a spectroscopic probe to detect the collective vibrational mode in vast molecular systems and investigate dielectric properties of various materials. Recent technological advances in generating intense THz radiation and the emergence of THz plasmonics operating with nanoscale structures have opened up new pathways toward THz applications. Here, we present a new opportunity in engineering the state of matter at the atomic scale using THz wave and a metallic nanostructure. We show that a medium strength THz radiation of 22 kV/cm can induce ionization of ambient carbon atoms through interaction with a metallic nanostructure. The prepared structure, made of a nano slot antenna and a nano island located at the center, acts as a nanogap capacitor and enhances the local electric field by two orders of magnitudes thereby causing the ionization of ambient carbon atoms. Ionization and accumulation of carbon atoms are also observed through the change of the resonant condition of the nano slot antenna and the shift of the characteristic mode in the spectrum of the transmitted THz waves.

Acoustic Performance of 3D Printed Nanocomposite Earmuff.

Introduction:Hearing protection devices are one of the primary noise reduction tools in developing countries. This study is intended to produce and apply acrylonitrile butadiene styrene (ABS)/clay nanocomposites to fabricate a laboratory single cup earmuffs and then compare it with double cup and single cup pure ABS earmuffs in terms of noise attenuation performance and comfort. In addition, the noise attenuation performance of single cup pure ABS earmuffs is compared with double cup pure ABS earmuffs.Methods:ABS/nanoclay filament was fabricated using a twin screw extruder. A three dimensional (3D) printing machine and a 3D model of earcup, designed by solid work software, were applied to print single and double cup earmuffs using ABS/nanoclay composite and pure ABS filaments. Finally, using an acoustic test fixture, objective noise attenuation test was performed on three different types of earmuffs, including with and without nano material and a secondary cup. Moreover, earmuffs weight was measured as a comfort component.Results:Insertion loss and calculated noise reduction rating (NRR) of single cup ABS/nanoclay earmuffs (NRR=19.4 dB) and double cup pure ABS earmuffs (NRR=18.93 dB) were improved in comparison with single cup pure ABS earmuffs (NRR=15.7 dB). Additionally, both single cup earmuffs were significantly lighter than double cup earmuffs. Although single cup nano and double cup earmuffs had nearly the same attenuation performance, single cup nano earmuffs were 74 gr lighter than double cup earmuffs, so with reference to comfort, single cup nano earmuffs will probably be more acceptable.Conclusions:From this survey it might be concluded that, even though single cup ABS/nanoclay earmuffs was lighter than double cup pure ABS earmuffs, it had approximately more attenuation performance in comparison with double cup pure ABS earmuffs. Consequently, users are probably more prone to wear light- weight single cup ABS/nanoclay earmuffs as a result of improved comfort. In short, ABS/nanoclay composite can be considered a good choice in products with the necessity of high acoustic performance and low weight.