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Advances in Natural Sciences: Nanoscience and Nanotechnology

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This is an Open Access Journal

Open Access journal
ISSN (Print) 2043-6254 - ISSN (Online) 2043-6262
Published by Institute of Physics (IOP)

[69 journals]

Silver nanoparticles: synthesis, properties, toxicology, applications and perspectives
- Authors: Quang Huy Tran; Van Quy Nguyen Anh-Tuan Le
  First page: 033001
  Abstract: In recent years the outbreak of re-emerging and emerging infectious diseases has been a significant burden on global economies and public health. The growth of population and urbanization along with poor water supply and environmental hygiene are the main reasons for the increase in outbreak of infectious pathogens. Transmission of infectious pathogens to the community has caused outbreaks of diseases such as influenza ( A/H 5 N 1 ), diarrhea (Escherichia coli), cholera (Vibrio cholera), etc throughout the world. The comprehensive treatments of environments containing infectious pathogens using advanced disinfectant nanomaterials have been proposed for prevention of the outbreaks. Among these nanomaterials, silver nanoparticles (Ag-NPs) with unique properties of high antimicrobial activity have attracted much interest from scientists and technologists to develop nanosilver-based disinfectant products. This article aims to...
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-05-13T23:00:00Z
  Issue No: Vol. 4, No. 3 (2013)
Controlled synthesis of size-tunable nickel and nickel oxide nanoparticles using water-in-oil microemulsions
- Authors: Ajeet Kumar; Amit Saxena, Arnab De, Ravi Shankar Subho Mozumdar
  First page: 025009
  Abstract: Industrial demands have generated a growing need to synthesize pure metal and metal–oxide nanoparticles of a desired size. We report a novel and convenient method for the synthesis of spherical, size tunable, well dispersed, stable nickel and nickel oxide nanoparticles by reduction of nickel nitrate at room temperature in a TX-100/ n -hexanol/cyclohexane/water system by a reverse microemulsion route. We determined that reduction with alkaline sodium borohydrate in nitrogen atmosphere leads to the formation of nickel nanoparticles, while the use of hydrazine hydrate in aerobic conditions leads to the formation of nickel oxide nanoparticles. The influence of several reaction parameters on the size of nickel and nickel oxide nanoparticles were evaluated in detail. It was found that the size can be easily controlled either by changing the molar ratio of water to surfactant or by simply altering the concentration of the reducing agent. The morphology and structure of the nanopart...
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-04-18T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
Influence of fabrication conditions on giant magnetocaloric effect of Ni–Mn–Sn ribbons
- Authors: Huy Dan Nguyen; Tran Huu Do, Hai Yen Nguyen, Thi Thanh Pham, Huu Duc Nguyen, Thi Nguyet Nga Nguyen, Dang Thanh Tran, The Long Phan Seong Cho Yu
  First page: 025011
  Abstract: The magnetocaloric effect of Ni 50 Mn 50− x Sn x ribbons ( x = 11–15) prepared by using melt-spinning and subsequent annealing has been investigated. The x-ray diffraction data of specimens show that all the samples are partially crystallized with Ni 2 MnSn phase. The magnetic transitions of these ribbons strongly depend on Sn-concentration and annealing process. Particularly, the antiferromagnetic–ferromagnetic transition is just observed at a narrow range of the Sn-concentration ( x = 12–14). The positive magnetic entropy changes occurring at the transition temperature of the antiferromagnetic phase are quite large, Δ S m max = 5.7 J kg −1 K −1 (for x = 13) with external magnetic field change Δ H = 12 kOe. Besides that, the negative magnetic entropy changes take place near Curie temperature and their magnitude is also large, Δ S m max
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-04-29T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
Carbon nanotubes materials and their application to guarantee safety from exposure to electromagnetic fields
- Authors: Anh Son Hoang; Hong Nhung Nguyen, Hung Thang Bui, Anh Tuan Tran, Van Anh Duong Van Binh Nguyen
  First page: 025012
  Abstract: Multi-walled carbon nanotubes (MWCNTs)-filled epoxy composites and poly(methyl methacrylate) (PMMA) coatings were prepared by mechanical grinding with the use of a planetary ball mill. Electromagnetic interference shielding effectiveness, electromagnetic absorption and reflection properties of the materials were investigated. With MWCNTs loadings higher than 20 wt%, epoxy/MWCNTs composites and PMMA/MWCNTs coatings also exhibited the full capability of shielding from more than 99% electromagnetic radiation at the 100 MHz–14 GHz frequency range.
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-04-29T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
Improved performances in light-emitting diodes based on a semiconductor TiO 2 nano cluster buffer layer
- Authors: Phuong Hoai Nam Nguyen; Nang Dinh Nguyen
  First page: 025013
  Abstract: Ultra-thin films of TiO 2 nano clusters were fabricated and characterized by field- emission scanning electron microscopy (FE-SEM) and transmittance measurements. The x-ray spectra of the TiO 2 nano crystals were also studied. The performances of the devices based on the blended conducting polymer are improved by inserting a semiconducting layer of TiO 2 nano cluster into the emissive poly[9-vinylcarbarzole] (PVK)/ poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and Al cathode. The organic light-emitting diodes (OLEDs) show high efficiency and good stability with turn-on voltage lower than 3 V and current density higher than 0.5 mA mm −2 .
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-04-29T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
Electrosynthesis of polyaniline–mutilwalled carbon nanotube nanocomposite films in the presence of sodium dodecyl sulfate for glucose biosensing
- Authors: Trong Huyen Le; Ngoc Thang Trinh, Le Huy Nguyen, Hai Binh Nguyen, Van Anh Nguyen, Dai Lam Tran Tuan Dung Nguyen
  First page: 025014
  Abstract: Polyaniline–mutilwalled carbon nanotube (PANi–MWCNT) nanocomposites were electropolymerized in the presence of sodium dodecyl sulfate (SDS) onto interdigitated platinum-film planar microelectrodes (ID μ E). The MWCNTs were first dispersed in SDS solution then mixed with aniline and H 2 SO 4 . This mixture was used to electro-synthesize PANi–MWCNT films with potentiostatic method at E = + 0.90 V (versus SCE). The PANi–MWCNT films were characterized by cyclic voltammetry (CV) and scanning electron microscopy (SEM). The results show that the PANi–MWCNT films have a high electroactivity, and a porous and branched structure that can increase the specific surface area for biosensing application. In this work the PANi–MWCNT films were applied for covalent immobilization of glucose oxidase (GOx) via glutaraldehyde agent. The GOx/PANi–MWCNT/ID μ E was studied using cyclic voltammetric and chronoamperometric techniques. The effect of several interferences...
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-04-29T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
A method to obtain homogeneously dispersed carbon nanotubes in Al powders for preparing Al/CNTs nanocomposite
- Authors: Van Trinh Pham; Van An Nguyen, Hung Thang Bui, Danh Chung Le, Van Chuc Nguyen, Van Luan Nguyen, Dinh Phuong Doan Ngoc Minh Phan
  First page: 025015
  Abstract: Recently carbon nanotubes (CNTs)-reinforced metal matrix composites (MMCs) have attracted increasing attention due to their promising properties. Most research on metallic matrix–CNTs composites (MMCs–CNTs) show that uniform dispersion of CNTs has been by far the most significant challenge in the field of CNTs-reinforced composites. In this research we will present an approach to obtain homogeneously dispersed CNTs in Al powders for preparing Al/CNTs nanocomposite. A novel polyester binder-assisted (PBA) mixing method was used for achieving uniform dispersion of CNTs, and power metallurgy (PM) technique was used for preparing Al/CNTs nanocomposite. The distribution quality of CNTs in Al matrix nanocomposites was also qualified based on image analysis technique. The morphologies, structures and mechanical properties of the Al/CNTs nanocomposite were also investigated in detail by scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, x-ray diffraction (XRD...
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-04-29T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
Simple crack propagation model of pressure-sensitive adhesives
- Authors: Shinobu Sekine; Toshihiro Kawakatsu
  First page: 025016
  Abstract: We propose a simple mechanical model describing viscoelasticity, cavitation growth and crack propagation during the debonding process in pressure-sensitive adhesives (PSAs). Typical materials of PSA are made of block copolymers and they are usually very soft and highly dissipative, and can stick on a variety of surfaces under low pressure in short time. The debonding process of PSA is governed by very complicated dynamics, for example, deformation of the adhesive layer, cavity expansion and coalescence. Our model is a modified version of that proposed by Yamaguchi et al (2006 Eur. Phys. J. E 20 7). We extended his simple model to be applicable to the final rupture process and applied the model to some cases, where we studied the effects of the change of PSA layer's thickness, separation speed and friction coefficient. Our results are qualitatively in good agreement with the experimental data.
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-05-07T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
Electric field-controlled magnetization in exchange biased IrMn/Co/PZT multilayers
- Authors: D T Huong Giang; N H Duc, G Agnus, T Maroutian P Lecoeur
  First page: 025017
  Abstract: Electric-field modulating exchange bias and near 180° deterministic magnetization switching at room temperature are demonstrated in simple antiferromagnetic/ferromagnetic/ferroelectric (AFM/FM/FE) exchange-coupled multiferroic multilayers of IrMn/Co/PZT. A rather large exchange bias field shift up to Δ H ex / H ex = 500% was obtained. This change governs mainly the electric-field strength rather than the applied current. It is explained as being realized through the competition between the electric-field induced uniaxial and unidirectional anisotropies. These results show good prospects for low-power spintronic devices.
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-05-07T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)
Magnetic and magnetocaloric properties in La–(Fe–Co)–Si
- Authors: Hai Yen Nguyen; Thi Thanh Pham, Huu Duc Nguyen, Dang Thanh Tran, The-Long Phan, Cho Yu Seong Huy Dan Nguyen
  First page: 025018
  Abstract: In this paper we present the results of study on the magnetic and magnetocaloric properties of LaFe 11− x Co x Si 2 ( x = 0, 1, 2, 3 and 4) ribbons prepared by using melt-spinning method. The results show that the glass forming ability (GFA) of the alloy is considerably influenced by the addition of Co. With increasing Co-concentration of the alloy, Curie temperature ( T C ) increases from ∼220 K (for x = 0) to ∼500 K (for x = 4). The maximum magnetic entropy change Δ S M max of the alloy, which is achieved near T C , is larger than 1.2 J kg −1 K −1 (under magnetic change Δ H = 12 kOe) for all the concentrations of Co. This has a significant meaning for magnetic refrigeration applications.
  Citation: Advances in Natural Sciences: Nanoscience and Nanotechnology
  PubDate: 2013-05-07T23:00:00Z
  Issue No: Vol. 4, No. 2 (2013)