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1 – 10 of 85
Article
Publication date: 18 May 2012

E. Yan, Y. Wang, T. Jing, D. Zhang, C. Wang and J. Zhang

The purpose of this paper is to investigate the effects of preparation process and amounts of starting materials on the morphology of chitosan‐silica (CS‐silica) hybrid hollow…

Abstract

Purpose

The purpose of this paper is to investigate the effects of preparation process and amounts of starting materials on the morphology of chitosan‐silica (CS‐silica) hybrid hollow nanospheres.

Design/methodology/approach

A simple method coupling sol‐gel process and in situ self‐assembly was used to prepare CS‐silica nanospheres from the solution containing chitosan‐poly (acrylic acid) (CS‐PAA) nanoparticles, tetraethoxyorthosilicate (TEOS) and polyvinylpyrrolidone (PVP). The morphology of CS‐silica hybrid hollow nanospheres was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The chemical structures of CS‐PAA nanoparticles and CS‐silica nanospheres were characterised by FT‐IR spectra.

Findings

The size and morphology of CS‐silica nanospheres was largely dependent on the starting amounts of TEOS, PVP and ammonia. Moreover, the reaction time can also affect the structures of the hybrid nanospheres.

Research limitations/implications

The dispersibility of CS‐silica nanospheres was not good enough and the conglutination was inevitable to some extent.

Practical implications

The coupling of sol‐gel technology and in situ self‐assembly opened a new gateway for preparing other organic/inorganic composite nanoparticles. This kind of material could be used as a slow release agent for biocides in coatings/paints.

Originality/value

The hybrid CS‐silica nanospheres showed obvious hollow structures. The morphology of nanospheres can be efficaciously controlled via adjusting the starting amounts of PVP, TEOS and ammonia, and the stirring time. The obtained CS‐silica hybrid nanospheres will have potential applications in such as drug delivery and controlled release.

Details

Pigment & Resin Technology, vol. 41 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 December 2005

Robert Bogue

To describe a new high sensitivity, nanotechnology‐based technique for detecting DNA and disease‐related proteins.

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Abstract

Purpose

To describe a new high sensitivity, nanotechnology‐based technique for detecting DNA and disease‐related proteins.

Design/methodology/approach

Gold nanoparticles and magnetic microparticles are bound to single‐stranded DNA molecules that are complementary to segments of the target DNA. The nanoparticles also link to hundreds of strands of “barcode” DNA and in the presence of the target, each molecule binds to a gold nanoparticle and a magnetic microparticle. Applying a magnetic field enables the separation of the target molecules and their attachments. The DNA is removed from the molecules and detected by a chip‐based DNA procedure. As each nanoparticle links to a large number of strands of DNA, the method amplifies the signal from each target molecule. The technique can also detect proteins by replacing the complimentary DNA with antibodies.

Findings

This research shows that this technique can detect very low concentrations of DNA and proteins. Ten copies of anthrax DNA were detected in 30 μl of solution, a sensitivity comparable to polymerase chain reaction, and 18‐20 PSA molecules were detected in a 10 μl sample, a level of detection that is six orders of magnitude more sensitive than conventional assays. Recent research has also shown that the assay can detect ADDLs, which are biomarkers for Alzheimer's disease. The technologies are now being commercialised by Nanosphere, Inc.

Originality/value

These developments offer prospects in a wide range of clinical applications such as the rapid and simple diagnosis of a variety of diseases and single nucleotide polymorphisms tests for the detection of hypercoagulation disorders. Other potential applications include homeland security and environmental monitoring.

Details

Sensor Review, vol. 25 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 31 March 2020

Chunlan Liu, Yang Gao, YaChen Gao, Yong Wei, Ping Wu and Yudong Su

This paper aims to clarify the relationship between the performance of the metal nanoparticles and the sensitivity of the fiber surface plasma resonance (SPR) sensor. It proposes…

Abstract

Purpose

This paper aims to clarify the relationship between the performance of the metal nanoparticles and the sensitivity of the fiber surface plasma resonance (SPR) sensor. It proposes modeling the sensing effects of a single-mode fiber SPR sensor with a cone angle structure decorated with metal nanoparticles. This study uses the metal nanoparticles to the realize enhanced sensitivity of refractive index sensing.

Design/methodology/approach

This paper opted for an exploratory study using a simulation approach of finite-difference time-domain (FDTD). Specifically, the effect of size, the material and the shape of the metal nanoparticle on sensing performance are investigated theoretically.

Findings

In conclusion, it is evident that the localized SPR (LSPR) effect weakens as the diameter of the gold nanosphere increases, the SPR effect enhances and the SPR sensitivity increases first and then decreases. The metal nanoparticle with the different materials and different shapes also have different LSPR and SPR sensitivity and wavelength length dynamic range. The investigation shows that, by changing parameters, the reflection spectra of the fiber SPR sensor exhibit an obvious transition from LSPR to SPR characteristics, and enhanced sensitivity of the refractive index is realized.

Originality/value

This paper fulfills an identified need to study how the sensitivity of the fiber SPR sensor can be enhanced by the metal nanoparticle. After the optimization of parameters, the sensitivity of 5,140 nm/RIU is achieved, which provides a new research direction for sensitivity enhancement of fiber SPR sensor.

Details

Sensor Review, vol. 40 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 29 May 2023

Ting Li, Xianggang Chen, Junhai Wang, Lixiu Zhang, Xinran Li and Xiaoyi Wei

The purpose of this study is to prepare ZnFe2O4 nanospheres, sheet MoS2 and three ZnFe2O4@MoS2 core-shell composites with various shell thicknesses, and add them to the base oil…

Abstract

Purpose

The purpose of this study is to prepare ZnFe2O4 nanospheres, sheet MoS2 and three ZnFe2O4@MoS2 core-shell composites with various shell thicknesses, and add them to the base oil for friction and wear tests to simulate the wear conditions of hybrid bearings.

Design/methodology/approach

Through the characterization and analysis of the morphology of wear scars and the elemental composition of friction films, the tribological behavior and wear mechanism of sample materials as lubricant additives were investigated and the effects of shell thickness and sample concentration on the tribological properties of core–shell composite lubricant additives were discussed.

Findings

The findings demonstrate that each of the five sample materials can, to varying degrees, enhance the lubricating qualities of the base oil and that the core–shell nanocomposite sample lubricant additive has superior lubricating properties to those of ZnFe2O4 and MoS2 alone, among them ZnFe2O4@MoS2-2 core–shell composites with moderate shell thickness performed most ideally. In addition, the optimal concentration of the ZnFe2O4@MoS2 lubricant additive was 0.5 Wt.%, and a concentration that was too high led to particle deposition and affected the friction effect.

Originality/value

In this work, ZnFe2O4@MoS2 core–shell composites were synthesized for the first time using ZnFe2O4 as the carrier and the lubrication mechanism of core–shell composites and single materials were compared and studied, which illustrated the advantages of core–shell composite lubricant additives. At the same time, the influence of different shell thicknesses on the lubricant additives of core–shell composites was studied.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2022-0367/

Details

Industrial Lubrication and Tribology, vol. 75 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 4 September 2017

N. Köken, M.E. Çamoglu and E.A. Güvel

This paper aims to synthesise block copolymers (PPy-b-ENP) of pyrrole (Py) and ethoxylated nonyl phenols (ENP) via redox systems in presence of ceric ammonium nitrate (CAN) at…

75

Abstract

Purpose

This paper aims to synthesise block copolymers (PPy-b-ENP) of pyrrole (Py) and ethoxylated nonyl phenols (ENP) via redox systems in presence of ceric ammonium nitrate (CAN) at room temperature. The initiating radical was formed on reducing organic compound which in turn initiated polymerisation to give diblock copolymers containing chain ends of ENPs and polypyrrole (Ppy). The effects of the concentration of Ce+4 salt, ENPs and Py on both the yield and electrical conductivities of corresponding polymers were studied.

Design/methodology/approach

In total, 0.1 M stock solution of CAN:100 ml 1 M HNO3 was prepared freshly (7 ml HNO3 dissolved in 100 ml water) and used in 50 ml of 0.1 M CAN solution (2.7438 g CAN dissolved in 50 ml nitric acid solution). The reducing compound (Py) was dissolved in water. Py and ENP were added slowly to the flask with vigorous stirring. The content of the flask was flushed with oxygen-free nitrogen. The resulting copolymers were characterised with spectroscopic methods like Fourier transform infrared spectroscopy and scanning electron microscope.

Findings

In this study, DMSO-slightly soluble Py copolymers were produced with ENPs. The conductivities of copolymers were found to be in the range of 10-1 to 10-4 S/cm. Soluble and processable conductive polymers were developed.

Research limitations/implications

In this study, the water solubility of ENPs diminishes the conductivity of copolymer because of its surfactant structure. When the CAN/Py ratio was increased, PPys and copolymers with both higher yield and lower conductivity values were obtained. The results indicated that solubilities and the yield of the polymers synthesised in the presence of ENP have increased considerably. ENP caused degradative chain transfer reaction to become significant compared with bimolecular termination, so the yield decreased with increasing ENP concentration about 20 g/l. Results showed that yield of the copolymers strongly depends on Ce+4 concentrations while of copolymers were measured to be 10-3 S/cm.

Practical implications

PPy-b-ENP diblock copolymers were prepared with Ce+4 as an oxidation agent in a single step.

Social implications

These slightly soluble and conductive copolymers may overcome difficulties in the applications of PPy homopolymers and open new application areas.

Originality/value

PPy-b-ENPs of lightly soluble (in DMSO) and conductive (10-2 S/cm) copolymers have been synthesised in one step. The results indicate that the surface of the copolymer is composed of well-distributed nanospheres with an average particle diameter of 35-400 nm.

Details

Pigment & Resin Technology, vol. 46 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 3 August 2021

Rui Wang, Chunlan Liu, Yong Wei and Yudong Su

This paper aims to study the sensitivity enhancement effect of the gold nanorod on fiber surface plasmon resonance (SPR) sensor. It proposes modeling the sensing effects of fiber…

189

Abstract

Purpose

This paper aims to study the sensitivity enhancement effect of the gold nanorod on fiber surface plasmon resonance (SPR) sensor. It proposes modeling the sensing effects of fiber SPR sensor decorated with metal nanoparticles. By using simulation and experiment, the sensitivity enhancement effect of the gold nanorod was studied and demonstrated.

Design/methodology/approach

The paper opted for an exploratory study using simulation approach of finite-difference time-domain. Specifically, the effect of ratios and aspect ratios of gold nanorod on sensing performance are investigated theoretically. Based on the mathematical models, the validation experiments by using the gold nanorod with the aspect ratios of 5.1 were done to verify the sensitivity enhancement effect of the gold nanorod.

Findings

In conclusion, it is evident that with the increases of the aspect ratios, the sensing sensitivity of the refractive index increases first, then gradually stabilizes or decreases. After parameter optimization, the ratios and aspect ratios of gold nanorod are chosen to be 8 nm and 12.5, respectively, which makes the optimal refractive index sensitivity of 4465.53 nm/RIU be realized. In addition, the validation experiments by using the gold nanorod with the aspect ratios of 5.1 verify the sensitivity enhancement effect of the gold nanorods.

Originality/value

This paper proposes and demonstrates a new method for the sensitivity enhancement of fiber SPR sensor. After parameter optimization, the maximum sensitivity of 4465.53 nm/RIU was achieved by using 8 nm gold nanorods with the aspect ratios of 12.5. To verify the sensitivity enhancement of the gold nanorods, the authors also did the validation experiments. The testing results indicated that after the decoration of the gold nanorods, the sensitivity of the sensing probe increases from 2190.57 nm/RIU to 2693.24 nm/RIU, which demonstrates the sensitivity enhancement effect of the gold nanorods.

Details

Sensor Review, vol. 41 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Content available
Article
Publication date: 15 May 2009

61

Abstract

Details

Aircraft Engineering and Aerospace Technology, vol. 81 no. 3
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 4 February 2014

Zhengfeng Jia, Yan-qiu Xia, Xin Shao and San-ming Du

– The purpose of this paper is to investigate the tribological properties of poly-alpha-olefin (PAO) with nano/microstructure core-shell lanthanum borate-SiO2 composites (OCLS).

Abstract

Purpose

The purpose of this paper is to investigate the tribological properties of poly-alpha-olefin (PAO) with nano/microstructure core-shell lanthanum borate-SiO2 composites (OCLS).

Design/methodology/approach

Oleic acid-capped core-shell lanthanum borate-SiO2 composites were synthesized by an easy way. The composites were characterized by means of Fourier transform-infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and thermo gravimetric analysis (TGA). The friction and wear behaviors of the quenched AISI 1045 steel specimens sliding against AISI 52100 steel under the lubrication of PAO containing OCLS were comparatively investigated with PAO containing SiO2 additive on an Optimol SRV reciprocating friction and wear tester. On the other hand, the tribological properties of the PAO containing OCLS were also investigated on four-ball tester.

Findings

The diameter of OCLS was about 20 nm, and the thickness of the SiO2 shell was less than 5 nm. The ratio of oleic acid (OA) is about 15 percent. The PAO containing OCLS possesses much better tribological properties than that of pure PAO and PAO containing SiO2 additive.

Originality/value

The PAO+OCLS possess a better friction reducing and antiwear properties than pure PAO. The new additive can improve the tribological ability of machinery.

Details

Industrial Lubrication and Tribology, vol. 66 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 15 September 2021

Srinivas Rao Sriram, Saidireddy Parne, Venkata Satya Chidambara Swamy Vaddadi, Damodar Edla, Nagaraju P., Raji Reddy Avala, Vijayakumar Yelsani and Uday Bhasker Sontu

This paper aims to focus on the basic principle of WO3 gas sensors to achieve high gas-sensing performance with good stability and repeatability. Metal oxide-based gas sensors are…

Abstract

Purpose

This paper aims to focus on the basic principle of WO3 gas sensors to achieve high gas-sensing performance with good stability and repeatability. Metal oxide-based gas sensors are widely used for monitoring toxic gas leakages in the environment, industries and households. For better livelihood and a healthy environment, it is extremely helpful to have sensors with higher accuracy and improved sensing features.

Design/methodology/approach

In the present review, the authors focus on recent synthesis methods of WO3-based gas sensors to enhance sensing features towards toxic gases.

Findings

This work has proved that the synthesis method led to provide different morphologies of nanostructured WO3-based material in turn to improve gas sensing performance along with its sensing mechanism.

Originality/value

In this work, the authors reviewed challenges and possibilities associated with the nanostructured WO3-based gas sensors to trace toxic gases such as ammonia, H2S and NO2 for future research.

Details

Sensor Review, vol. 41 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 19 June 2007

Giovanni Miano, Fabio Villone and Walter Zamboni

To study optical resonances in metallic nanoparticles.

Abstract

Purpose

To study optical resonances in metallic nanoparticles.

Design/methodology/approach

The metallic nanoparticle is modeled as a dielectric body dispersive in frequency with assigned dielectric constant. The electric field is expressed as function of the charge distribution through an integral formulation. By imposing the boundary conditions on the nanoparticle surface, the equations for the induced charge in the nanoparticle is obtained. The numerical solution of such equations allows to treat arbitrary geometries and to estimate the effects of deviations from ideality on the resonance values.

Findings

Plasmon resonances in metallic nanoparticles can be safely studied with an electro‐quasistatic approximation. The resonance frequencies depend greatly on the details of the geometry of the nanoparticles.

Research limitations/implications

The free‐space wavelength is supposed to be much greater than the largest characteristic dimension of the nanoparticles. Consequently, a electro‐quasistatic model is used to evaluate the distribution of the charges induced in the metallic nanoparticle.

Originality/value

Two methods are presented for the evaluation of the resonance frequencies starting from the numerical solution for a given geometry.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

1 – 10 of 85