http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Sun, 19 May 2013 16:20:55 +0000 http://www.hindawi.com/journals/jnm/2013/767249/ We elaborate on the cross-sectional deformation of carbon nanotubes embedded into a self-contracting host medium. The continuum elastic approach is used to formulate the mechanical energy of both the embedded nanotubes and the self-contracting outer medium with finite thickness. Our formula allows us to evaluate the critical radial pressure applied on the interface between the embedded nanotube and the outer contracting medium as well as the deformation mode that arises immediately above the critical pressure. An interesting mechanical implication of the embedding effect, that is, the power-law dependence of the critical pressure on the elastic modulus of the medium, is deduced by the theoretical approach established. Motohiro Sato, Hisao Taira, Tetsuro Ikeda, and Hiroyuki Shima Copyright © 2013 Motohiro Sato et al. All rights reserved. Sun, 19 May 2013 13:19:48 +0000 http://www.hindawi.com/journals/jnm/2013/468105/ To perform single-molecule studies of the T7 RNA polymerase, it is crucial to visualize an individual T7 RNA polymerase, for example, through a fluorescent signal. We present a novel complex combining two different molecular functions, an active T7 RNA polymerase and a highly luminescent nanoparticle, a quantum dot. The complex has the advantage of both constituents: the complex can traffic along DNA and simultaneously be visualized, both at the ensemble and at the single-molecule level. The labeling was mediated through an in vivo biotinylation of a His-tagged T7 RNA polymerase and subsequent binding of a streptavidin-coated quantum dot. Our technique allows for easy purification of the quantum dot labeled T7 RNA polymerases from the reactants. Also, the conjugation does not alter the functionality of the polymerase; it retains the ability to bind and transcribe. Mette Eriksen, Peter Horvath, Michael A. Sørensen, Szabolcs Semsey, Lene B. Oddershede, and Liselotte Jauffred Copyright © 2013 Mette Eriksen et al. All rights reserved. Wed, 15 May 2013 12:04:54 +0000 http://www.hindawi.com/journals/jnm/2013/706354/ This study was to develop antibodies conjugated fluorescent dye-doped silica nanoparticles (FDS-NPs) aiming to increase signals for the rapid detection of Escherichia coli O157:H7 with glass slide method. The FDS-NPs were produced with microemulsion/sol-gel techniques resulting in spherical in shape with 47 ± 6 nm in diameter. The particles showed high intensity and stable orange color Rubpy luminescent dye. The XRD spectrum showed a broad diffraction peak in the range of – (centered at ) indicating an amorphous structure. Surface modifications for bioconjugation with affinity chromatography purified (IgGs) antibodies were successful. The properties were evident from FTIR spectra at 1631.7 . Results indicated that nanoparticles could attach onto cells of E. coli O157:H7 coated on a glass slide, and give distinctively bright color under epifluorescence microscope (400x). It was shown that FDS-NPs could detect a very low amount of cells of E. coli O157:H7 (16 CFU in 10 ml) in 60 min. The phosphate buffered saline (PBS) with ionic strength of 1.70 gave zeta potential of good particle dispersion (−40 mV). This work demonstrated that highly sensitive bioconjugated E. coli O157:H7 FDS-NPs were successfully developed with a potential to be used for the rapid detection of E. coli O157:H7 in foods. Pravate Tuitemwong, Nut Songvorawit, and Kooranee Tuitemwong Copyright © 2013 Pravate Tuitemwong et al. All rights reserved. Mon, 13 May 2013 13:04:25 +0000 http://www.hindawi.com/journals/jnm/2013/682832/ The paper is devoted to the analysis of the correlation effects and manifestations of general properties of 1D systems (such as spatial heterogeneity that is associated with strong density fluctuations, the lack of phase transitions, the presence of frozen disorder, confinement, and blocked movement of nuclear particle by its neighbours) in nonequilibrium phenomena by considering the four examples. The anomalous transport in zeolite channels is considered. The mechanism of the transport may appear in carbon nanotubes and MOF structures, relaxation, mechanical properties, and stability of nonequilibrium states of free chains of metal atoms, non-Einstein atomic mobility in 1D atomic systems. Also we discuss atomic transport and separation of two-component mixture of atoms in a 1D system—a zeolite membrane with subnanometer channels. We discuss the atomic transport and separation of two-component mixture of atoms in a 1D system—zeolite membrane with subnanometer channels. These phenomena are described by the response function method for nonequilibrium systems of arbitrary density that allows us to calculate the dynamic response function and the spectrum of relaxation of density fluctuations 1D atomic system. V. D. Borman, I. V. Tronin, V. N. Tronin, V. I. Troyan, and O. S. Vasiliev Copyright © 2013 V. D. Borman et al. All rights reserved. Sun, 12 May 2013 12:35:19 +0000 http://www.hindawi.com/journals/jnm/2013/389634/ A facile method was developed to synthesize γ-MnO2 with different structures and surface properties in this paper. γ-MnO2 was prepared by oxidation of MnSO4 with Na2S2O8 at C for 2.0 h. γ-MnO2 formed at initial pH 1.0 (M1) and 8.5 (M2) was composed of MnH2O and MnH2O, respectively. The higher ratio of pyrolusite in M2 (%) than that in M1 (%) indicated that compared with M1, M2 would absorb more protons since the planar oxygen atoms in pyrolusite were incompletely coordinated and liable to absorb the protons. Meanwhile, the higher oxidation valence of Mn in M2 than that in M1 revealed that the Mn atoms in M2 were more liable to draw the electron density from the surface oxygen atoms in hydroxyl groups. The structural and compositional differences between M1 and M2 were the major reasons why M2 possessed a higher surface potential and a weaker ability to absorb Zn2+ ions. Chengxiang Liu, Jing Wang, Jiarui Tian, and Lan Xiang Copyright © 2013 Chengxiang Liu et al. All rights reserved. Sun, 12 May 2013 08:00:10 +0000 http://www.hindawi.com/journals/jnm/2013/627385/ The titanium dioxide (TiO2) photocatalysts were synthesized by a solvothermal process in highly alkaline 70 : 30 water : ketone solutions with a TiO2-P25 precursor and calcined at different temperatures. The ketone solvents, such as acetone and methyl ethyl ketone (MEK), had low boiling points (<100°C). The as-prepared samples were characterized by XRD, TEM, FTIR, UV-vis and Raman spectroscopy. The effects of the different solvents on the nanostructure, the morphology, and the photocatalytic performance of the TiO2 products were investigated. Nanotubes formed in water and water-MEK, while nanoparticle/nanowires formed in water-acetone and water-acetone-MEK. The ketone solvents played an important role in the improving nanostructure properties of these products, which affected their photocatalytic reactions. The results indicated that samples synthesized in solvents such as water and MEK had high adsorption and photocatalytic behaviors. The photocatalytic reactivity was the greatest for the TiO2 prepared in MEK and calcined at 100°C, which was even more reactive than the sample prepared in water and TiO2-P25 powder. Chau Thanh Nam, Wein-Duo Yang, and Le Minh Duc Copyright © 2013 Chau Thanh Nam et al. All rights reserved. Thu, 09 May 2013 14:55:23 +0000 http://www.hindawi.com/journals/jnm/2013/621378/ The influence of sodium dodecyl sulfonate (SDSN) on the formation of ZnO nanorods from ε-Zn(OH)2 was investigated in this paper. The ε-Zn(OH)2 precursor was prepared at room temperature using ZnSO4 and NaOH as the reactants and then converted to ZnO nanorods after aging at 80°C in NaOH solution containing a minor amount of sodium dodecyl sulfonate (SDSN). The experimental results and the molecular simulation revealed that the influence of SDSN on the formation of ZnO from ε-Zn(OH)2 should be attributed to the adsorption of SDSN on ε-Zn(OH)2 surfaces, which inhibited the dissolution of ε-Zn(OH)2 in NaOH solution, leading to the formation of the ZnO nanorods with a diameter of 50–200 nm, a length of 3.0–15.0 μm, and an aspect ratio of 30–100. Jing Wang, Chengxiang Liu, and Lan Xiang Copyright © 2013 Jing Wang et al. All rights reserved. Wed, 08 May 2013 17:26:29 +0000 http://www.hindawi.com/journals/jnm/2013/319840/ Graphene oxide (GO) has shown great potential to be used as fillers to develop polymer nanocomposites for important applications due to their special 2D geometrical structure as well as their outstanding mechanical, thermal, and electrical properties. In this work, GO was incorporated into phenol formaldehyde (PF) resin by in situ polymerization. The morphologies and structures of GO sheets were characterized by FTIR, XRD, and AFM methods. The structure and properties of the GO/PF nanocomposites were characterized using FTIR, XRD, DSC, and TGA methods. Effects of GO content, reactive conditions, and blending methods on the structure and properties of GO/PF nanocomposites were studied. It was found that due to the well dispersion of GO sheets in polymer matrix and the strong interfacial interaction between the GO sheets and PF matrix, the thermal stability and thermal mechanical properties of the GO/PF nanocomposites were greatly enhanced. Weihua Xu, Chun Wei, Jian Lv, Hongxia Liu, Xiaohua Huang, and Tianxi Liu Copyright © 2013 Weihua Xu et al. All rights reserved. Wed, 08 May 2013 15:24:34 +0000 http://www.hindawi.com/journals/jnm/2013/479109/ Water uptake characteristics of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV-) based composite tissue engineering (TE) scaffolds incorporating nanosized hydroxyapatite (nHA) have been investigated. The water absorption of these composite scaffolds obeyed the classical diffusion theory for the initial period of time. The diffusion coefficients of the composite scaffolds during the water absorption were much faster than those for the nonporous thin films, suggesting that the water uptake process depends on the presence of porosity and porous microstructure of the composite scaffolds. The incorporation of nHA increased the water uptake of both the composite scaffolds and thin films. It was also observed that the equilibrium uptake increased with the incorporation of nHA. This increase in the water uptake was largely due to the nHA particle aggregates in the microstructure of both composite scaffolds and thin films. The activation energy for diffusion was also determined using the Arrhenius equation for both porous scaffolds and thin films and the results suggested that the activation energy for scaffolds was lower than that for thin films. Naznin Sultana and Tareef Hayat Khan Copyright © 2013 Naznin Sultana and Tareef Hayat Khan. All rights reserved. Wed, 08 May 2013 14:42:51 +0000 http://www.hindawi.com/journals/jnm/2013/635673/ The resistance of several pristine and functional single-wall carbon nanotubes (SWNTs) deposited and dried on interdigitated electrode (IDE) chips was investigated to better understand how functional groups influence their resistivity. Without the external electrical field, the resistance was generally increased for the sulfonated and fluorinated SWNTs but not for COOH-SWNTs. With a 3 V electric field applied during depositing, while no change in resistance was found for the purified pristine SWNTs, fluorinated SWNTs, COOH SWNTs, and Ni-SWNTs, a significant decrease in resistance was observed in sulfonated SWNTs and unpurified pristine SWNTs, which could be due to the alignment of SWNTs in an electric field. The alignment of the sulfonated SWNTs is most likely due to the charge of the sulfate functional group. It is interesting to note that the alignment was found in the unpurified pristine SWNTs but not in the purified pristine ones which have lessened resistivity. The lower resistivity in the purified pristine SWNTs may be due to the smaller number (<5%) of impurities. The significance of this research is that hydrophilic COOH-SWNTs could be a better candidate than the hydrophobic pristine SWNTs for being used in many applications, especially in polymer nanocomposites. Yijiang Lu, Jing Li, and Haiping Hong Copyright © 2013 Yijiang Lu et al. All rights reserved. Tue, 07 May 2013 10:40:22 +0000 http://www.hindawi.com/journals/jnm/2013/616501/ Metal-organic frameworks (MOFs), also known as hybrid inorganic-organic materials, represent an emerging class of materials that have attracted the imagination of solid-state chemists because MOFs combine unprecedented levels of porosity with a range of other functional properties that occur through the metal moiety and/or the organic ligand. The purpose of this critical review is to give a representative and comprehensive overview of the arising developments in the field of functional metal-organic frameworks, including luminescence, magnetism, and porosity through presenting examples. This review will be of interest to researchers and synthetic chemists attempting to design multifunctional MOFs. Xiao-Lan Tong, Hai-Lu Lin, Jian-Hua Xin, Fen Liu, Min Li, and Xia-Ping Zhu Copyright © 2013 Xiao-Lan Tong et al. All rights reserved. Tue, 07 May 2013 09:14:09 +0000 http://www.hindawi.com/journals/jnm/2013/413692/ An electrospinning technique was used to fabricate TiO2 nanofibers for use as binder-free electrodes for lithium-ion batteries. The as-electrospun nanofibers were calcined at 400–1,000°C and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). SEM and TEM images showed that the fibers have an average diameter of ~100 nm and are composed of nanocrystallites and grains, which grow in size as the calcination temperature increases. The electrochemical properties of the nanofibers were evaluated using galvanostatic cycling and electrochemical impedance spectroscopy. The TiO2 nanofibers calcined at 400°C showed higher electronic conductivity, higher discharge capacity, and better cycling performance than the nanofibers calcined at 600, 800, and 1,000°C. The TiO2 nanofibers calcined at 400°C delivered an initial reversible capacity of 325 mAh·g−1 approaching their theoretical value at 0.1 C rate and over 175 mAh·g−1 at 0.3 C rate with limited capacity fading and Coulombic efficiency between 96 and 100%. Phontip Tammawat and Nonglak Meethong Copyright © 2013 Phontip Tammawat and Nonglak Meethong. All rights reserved. Mon, 29 Apr 2013 13:42:55 +0000 http://www.hindawi.com/journals/jnm/2013/203542/ Jianxin Zou, Craig Buckley, Huaiyu Shao, Gang Ji, and Kemin Zhang Copyright © 2013 Jianxin Zou et al. All rights reserved. Mon, 29 Apr 2013 10:32:21 +0000 http://www.hindawi.com/journals/jnm/2013/460870/ Nanoporous anodic aluminium oxide (AAO) has become increasingly important in biomedical applications over the past years due to its biocompatibility, increased surface area, and the possibility to tailor this nanomaterial with a wide range of surface modifications. AAO nanopores are formed in an inexpensive anodisation process of pure aluminium, which results in the self-assembly of highly ordered, vertical nanochannels with well-controllable pore diameters, depths, and interpore distances. Because of these outstanding properties AAO nanopores have become excellent candidates as nanostructured substrates for cell-interface studies. In this comprehensive review previous surveys on cell adhesion and proliferation on different AAO nanopore geometries and surface modifications are highlighted and summarised tabularly. Future applications of nanoporous alumina membranes in biotechnology and medicine are also outlined, for instance, the use of nanoporous AAO as implant modifications, coculture substrates, or immunoisolation devices. Dorothea Brüggemann Copyright © 2013 Dorothea Brüggemann. All rights reserved. Sun, 28 Apr 2013 16:00:42 +0000 http://www.hindawi.com/journals/jnm/2013/536291/ Chitosan (CS) nanoparticles have several distinct intrinsic advantages; however, their in vivo colloidal stability in biological fluids was not fully explored especially when carrying proteins. The present study aimed to investigate their colloidal stability using an ex vivo physiological model of fetal bovine serum (FBS) and human serum (HS). The stability of bovine-serum-albumin (BSA-) loaded nanoparticles was relatively higher in FBS than that in HS. Particle size of unloaded and BSA-loaded nanoparticles was statistically unchanged up to 24 h after incubation in FBS. However in HS, a significant increase in particle size from 144 ± 17 to 711 ± 22 nm was observed for unloaded nanoparticles and by 2.5-fold for BSA-loaded nanoparticle, at 24 h after incubation in HS. Zeta potential of both nanoparticles was less affected by the components in FBS compared to those in HS. A remarkable swelling extent was experienced for unloaded and BSA-loaded nanoparticles in HS, up to 54 ± 4% and 44 ± 5%, respectively. Morphology of unloaded and BSA-loaded nanoparticles was varied from smooth spherical and rod shape to irregular shape when incubated in FBS; however, form agglomerates when incubated in HS. These findings therefore suggest that HS is more reactive to cause colloidal instability to the chitosan nanoparticles compared to FBS. Haliza Katas, Zahid Hussain, and Siti Asarida Awang Copyright © 2013 Haliza Katas et al. All rights reserved. Tue, 23 Apr 2013 10:59:32 +0000 http://www.hindawi.com/journals/jnm/2013/154179/ Ta films were sputtered onto a glass substrate with thicknesses from 500 Å to 1500 Å under the following conditions: (a) as-deposited films were maintained at room temperature (RT), (b) films were postannealed at °C for 1 h, and (c) films were postannealed at °C for 1 h. X-ray diffraction (XRD) results revealed that the Ta films had a body-centered cubic (BCC) structure. Postannealing conditions and thicker Ta films exhibited a stronger Ta (110) crystallization than as-deposited and thinner films. The nanoindention results revealed that Ta thin films are sensitive to mean grain size, including a valuable hardness () and Young’s modulus (). High nanomechanical properties of as-deposited and thinner films can be investigated by grain refinement, which is consistent with the Hall-Petch effect. The surface energy of as-deposited Ta films was higher than that in postannealing treatments. The adhesion of as-deposited Ta films was stronger than postannealing treatments because of crystalline degree effect. The maximal and and the optimal adhesion of an as-deposited 500-Å-thick Ta film were 15.6 GPa, 180 GPa, and 51.56 mJ/mm2, respectively, suggesting that a 500-Å-thick Ta thin film can be used in seed and protective layer applications. Yuan-Tsung Chen Copyright © 2013 Yuan-Tsung Chen. All rights reserved. Tue, 23 Apr 2013 10:04:48 +0000 http://www.hindawi.com/journals/jnm/2013/291020/ Arg-Gly-Asp-Ser (RGDS), a typical membrane-permeable carrier peptide, was conjugated with mercaptoisobutyric acid-immobilized CdTe quantum dot (CTNPs) to enhance the intracellular uptake of quantum dots. Mean size of mercaptoisobutyric acid-immobilized quantum dots (37 nm) as determined by dynamic light scattering was increased up to 54 nm after RGDS immobilization. It was found, from in vitro cell culture experiment, that fibroblast (NIH 3T3) cells were well proliferated in the presence of RGDS-conjugated quantum dots (RCTNPs), and the intracellular uptake of CTNPs and RCTNPs was studied by means of ICP and fluorescence microscopy. As a result, the RCTNPs specifically bound to the membrane of NIH 3T3 cells and almost saturated after 6 hours incubation. The amount of RCTNPs uptaken by the cells was higher than that of CTNPs, demonstrating the enhancing effect of RGDS peptide conjugation on the intracellular uptake of quantum dots (QDs). Moon-Jeong Choi, R. Pierson, Yongmin Chang, Haiquing Guo, and Inn-Kyu Kang Copyright © 2013 Moon-Jeong Choi et al. All rights reserved. Tue, 23 Apr 2013 08:53:37 +0000 http://www.hindawi.com/journals/jnm/2013/254127/ Retinoic acid (R) grafted chitosan (C) copolymers with different degree of substitution of retinoic acid on the chitosan were synthesized. Retinoic acid targeted chitosan-albumin nanoparticles were prepared for targeted delivery of doxorubicin in hepatocellular carcinoma by coacervation method. Physical properties of nanoparticles including particle size, zeta potential, drug loading efficiency, and drug release profiles were studied. TEM micrographs were taken to see the morphology of nanoparticles. The cytotoxicity of doxorubicin-loaded nanoparticles was studied on HepG2 cells using MTT assay and their cellular uptake by fluorescence microscopy. FTIR and 1HNMR spectra confirmed successful production of RC conjugate which was used in production of the targeted RC-albumin nanoparticles. IC50 of drug loaded in these nanoparticles reduced to half and one-third compared to nontargeted nanoparticles and free drug, respectively. Jaleh Varshosaz, Farshid Hassanzadeh, Hojjat Sadeghi, Zahra Ghelich Khan, and Mahboobeh Rostami Copyright © 2013 Jaleh Varshosaz et al. All rights reserved. Mon, 22 Apr 2013 10:50:22 +0000 http://www.hindawi.com/journals/jnm/2013/409087/ New benzimidazole/benzothiazole imide derivatives with different alkyl substituent chains were designed and synthesized. Their gelation behaviors in 22 solvents were tested as novel low-molecular-mass organic gelators. The test showed that the alkyl substituent chains and headgroups of benzimidazole/benzothiazole residues in gelators played a crucial role in the gelation behavior of all compounds in various organic solvents. More alkyl chains in molecular skeletons in present gelators are favorable for the gelation of organic solvents. SEM and AFM observations revealed that the gelator molecules self-assemble into different aggregates from wrinkle, lamella and belt to dot with change of solvents. Spectral studies indicated that there existed different H-bond formation between imide groups and hydrophobic force of alkyl substituent chains in molecular skeletons. The present work may give some insights into design and character of new organogelators and soft materials with special molecular structures. Xihai Shen, Tifeng Jiao, Qingrui Zhang, Haiying Guo, Yaopeng Lv, Jingxin Zhou, and Faming Gao Copyright © 2013 Xihai Shen et al. All rights reserved. Mon, 22 Apr 2013 09:04:01 +0000 http://www.hindawi.com/journals/jnm/2013/278936/ An octadecyltrichlorosilane (OTS) superhydrophobic film using phase-separation method was prepared to demonstrate the anti-icing property of superhydrophobic surfaces. The superhydrophobicity of the film at − was investigated. It was found that the prepared OTS film retained its superhydrophobicity at − by the measurement of contact angle and roll-off angle. The icing progress of water droplets on the surface at − was observed. It showed that the prepared OTS film can markedly retard the icing process of water droplets and dramatically decrease the ice adhesion strength compared with that of blank surface, which can be used as anti-icing surfaces. Liang Ge, Guifu Ding, Hong Wang, Jinyuan Yao, Ping Cheng, and Yan Wang Copyright © 2013 Liang Ge et al. All rights reserved. Sun, 21 Apr 2013 10:47:07 +0000 http://www.hindawi.com/journals/jnm/2013/940389/ Owing to the superior mechanical, thermal, and electrical properties, graphene was a perfect candidate to improve the performance of lithium ion batteries. Herein, we review the recent advances in graphene-based composites and their application as cathode materials for lithium ion batteries. We focus on the synthesis methods of graphene-based composites and the superior electrochemical performance of graphene-based composites as cathode materials for lithium ion batteries. Libao Chen, Ming Zhang, and Weifeng Wei Copyright © 2013 Libao Chen et al. All rights reserved. Thu, 18 Apr 2013 13:10:47 +0000 http://www.hindawi.com/journals/jnm/2013/951858/ Integration of green chemistry principles to nanotechnology is one of the key issues in nanoscience research. Biological methods were used to synthesize metal and metal oxide nanoparticles of specific shape and size since they enhance the properties of nanoparticles in greener route. Plant-mediated methods devoid the use of toxic chemicals in the synthetic protocols which has adverse effects on the environment. Owing to the rich biodiversity of plants and their potential secondary constituents, plants and plant parts have gained attention in recent years as medium for nanoparticles' synthesis. In this review, we present the current status of nanoparticles synthesis using devastated crops. G. Madhumitha and Selvaraj Mohana Roopan Copyright © 2013 G. Madhumitha and Selvaraj Mohana Roopan. All rights reserved. Thu, 18 Apr 2013 10:45:49 +0000 http://www.hindawi.com/journals/jnm/2013/937019/ A 3-dimensionally ordered macroporous (3DOM) structure within a highly patterned cylindrical Sn-Ni alloy electrode was tailored by using various monodispersed polystyrene (PS) templates via a colloidal crystal templating process coupled with an electroplating process. The pore size and the wall thickness in the “inverse opal” 3DOM structure were increased with increasing the size of the PS template beads used in this study. The electrochemical performance of prepared electrodes was examined in order to reveal the correlation between the rate capability and the 3DOM structure. Except the electrode with 1.2 μm pores, the discharge capacities gradually decreased with increasing the current density, showing a capacity conservation ratio of 87% for the electrode with 0.5 μm pores and that of 84% for the electrode with 3.0 μm pores when the current density increased from 0.05 mA cm−2 to 2.0 mA cm−2. The reason for this difference is attributed to the fact that the wall thickness of less than 0.5 μm in the electrode with 1.2 μm pores has a short Li+ diffusion distance in solid-state walls. In addition, it is expected that high regularity of 3DOM structure plays a great role on rate capability. Consequently, the 3DOM structure prepared from 1.2 μm PS template beads was favorable for improving the rate capability. Yongcheng Jin, Hirokazu Munakata, Naoya Okada, and Kiyoshi Kanamura Copyright © 2013 Yongcheng Jin et al. All rights reserved. Wed, 17 Apr 2013 13:44:42 +0000 http://www.hindawi.com/journals/jnm/2013/174939/ The electrical discharge machining (EDM) system has been proven feasible as a rapid and efficient method for silver nanofluid preparation. This study prepared the silver nano-fluid via EDM and investigated the relationship between its process parameters and product characteristics. The prior study had found that the silver nano-fluid prepared by EDM contained both silver nanoparticles and silver ions. Silver ions had revealed the cause of the high suspension of the silver nanoparticles. To examine the relationship between the stability of silver nanofluid and the process parameters, this study quantified the relationship of process parameters to the material removal rate (MRR) of silver electrode and silver ion output rate (IOR) in the fluid, in order to achieve the most effective process parameter condition. Furthermore, the stability of silver nano-fluid was analyzed by various devices, including UV-Vis spectroscopy, size-distribution, and Zeta-potential analyzer. The effects of MRR, IOR, particle size, Zeta-potential, and optical properties of silver nanofluid under different process parameters are also discussed. Kuo-Hsiung Tseng, Heng-Lin Lee, Chih-Yu Liao, Kuan-Chih Chen, and Hong-Shiou Lin Copyright © 2013 Kuo-Hsiung Tseng et al. All rights reserved. Tue, 16 Apr 2013 18:57:02 +0000 http://www.hindawi.com/journals/jnm/2013/132919/ Two kinds of newly designed feed channels, for example, a spiral and a serpentine feed channels, for a bench-scale nanofiltration module were developed to improve the filtration performance. The experiments were carried out with the modules using a commercial flat NF membrane to investigate the effects of Reynolds number (Re) and flow channel structures on the flux of permeate and Mg2+ rejection. It was shown from the experimental results that although the effects of Reynolds number on fluxes were not obvious for the two new feed channels compared with a normal flow channel structure, the Mg2+ rejections varied apparently with Re. The Mg2+ rejections were almost the same for the modules with two new feed channels and larger than that for the module with normal feed channel. The numerical simulations of fluid flow in the three kinds of feed channels were completed at Re of 4800 to explain the phenomena. The results demonstrated that there was a secondary flow in both new feed channels, which strongly influences the Mg2+ rejection. The rejection increased with increasing average shear stress at the membrane wall. The spiral feed channel was the best one among the flow channel structures investigated. Zhi Chen, Ben Zhao, Fanglei Chen, and Jianming Li Copyright © 2013 Zhi Chen et al. All rights reserved. Tue, 16 Apr 2013 16:57:19 +0000 http://www.hindawi.com/journals/jnm/2013/127690/ Our focus in this study is on characterizing the capacitance voltage (C-V) behavior of Bernal stacking bilayer graphene (BG) and trilayer graphene (TG) as the channel of FET devices. The analytical models of quantum capacitance (QC) of BG and TG are presented. Although QC is smaller than the classic capacitance in conventional devices, its contribution to the total metal oxide semiconductor capacitor in graphene-based FET devices becomes significant in the nanoscale. Our calculation shows that QC increases with gate voltage in both BG and TG and decreases with temperature with some fluctuations. However, in bilayer graphene the fluctuation is higher due to its tunable band structure with external electric fields. In similar temperature and size, QC in metal oxide BG is higher than metal oxide TG configuration. Moreover, in both BG and TG, total capacitance is more affected by classic capacitance as the distance between gate electrode and channel increases. However, QC is more dominant when the channel becomes thinner into the nanoscale, and therefore we mostly deal with quantum capacitance in top gate in contrast with bottom gate that the classic capacitance is dominant. Hatef Sadeghi, Daniel T. H. Lai, Jean-Michel Redoute, and Aladin Zayegh Copyright © 2013 Hatef Sadeghi et al. All rights reserved. Tue, 16 Apr 2013 16:04:27 +0000 http://www.hindawi.com/journals/jnm/2013/101765/ Monolayer graphene is obtained by mechanical exfoliation using scotch tapes. The effects of thermal annealing on the tape residues and edges of graphene are researched. Atomic force microscope images showed that almost all the residues could be removed in N2/H2 at 400°C but only agglomerated in vacuum. Raman spectra of the annealed graphene show both the 2D peak and G peak blueshift. The full width at half maximum (FWHM) of the 2D peak becomes larger and the intensity ratio of the 2D peak to G peak decreases. The edges of graphene are completely attached to the surface of the substrate after annealing. Wang Xueshen, Li Jinjin, Zhong Qing, Zhong Yuan, and Zhao Mengke Copyright © 2013 Wang Xueshen et al. All rights reserved. Mon, 15 Apr 2013 18:53:13 +0000 http://www.hindawi.com/journals/jnm/2013/915461/ We investigated the influences of stacking architectures of the TiO2 nanoparticle layers on characteristics and performances of DSSCs. TiO2 nanoparticles of different sizes and compositions were characterized for their morphological and optical/scattering properties in thin films. They were used to construct different stacking architectures of the TiO2 nanoparticle layers for use as working electrodes of DSSCs. Characteristics and performances of DSSCs were examined to establish correlation of the stacking architectures of TiO2 nanoparticle layers with characteristics of DSSCs. The results suggest that the three-layer DSSC architecture, with sandwiching a 20 nm TiO2 nanoparticle layer between a 37 nm TiO2 nanoparticle layer and a hundred nm sized TiO2 back scattering/reflection layer, is effective in enhancing DSSC efficiencies. The high-total-transmittance 37 nm TiO2 nanoparticle layer with a larger haze can serve as an effective front scattering layer to scatter a portion of the incident light into larger oblique angles and therefore increase optical paths and absorption. Chih-Hung Tsai, Yu-Tang Tsai, Tsung-Wei Huang, Sui-Ying Hsu, Yan-Fang Chen, Yuan-Hsuan Jhang, Lun Hsieh, Chung-Chih Wu, and Yen-Shan Chen Copyright © 2013 Chih-Hung Tsai et al. All rights reserved. Mon, 15 Apr 2013 14:36:37 +0000 http://www.hindawi.com/journals/jnm/2013/762730/ Titanium dioxide (TiO2) is star materials due to its remarkable optical and electronic properties, resulting in various applications, especially in the fields of dye-sensitized solar cells (DSSCs). Photoanode is the most important part of the DSSCs, which help to adsorb dye molecules and transport the injected electrons. The size, structure, and morphology of TiO2 photoanode have been found to show significant influence on the photovoltaic performance of DSSCs. In this paper, we briefly summarize the synthesis and properties of one-dimensional (1D) TiO2 nanomaterials (bare 1D TiO2 nanomaterial and 1D hierarchical TiO2) and their photovoltaic performance in DSSCs. Jie Qu and Chao Lai Copyright © 2013 Jie Qu and Chao Lai. All rights reserved. Mon, 15 Apr 2013 10:58:20 +0000 http://www.hindawi.com/journals/jnm/2013/398357/ The synthesis of pure calcium carbonate nanocrystals using a high pressure homogeniser (HPH) via a microemulsion system produced uniform nanosized particles, which were characterised using transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The identified particles were aragonite polymorphs with a rod shape and were approximately 50 nm in size. The aragonite polymorph of calcium carbonate was prepared from biogenic materials, cockle shells, and exhibited unique characteristics (i.e., a higher density than that of calcite), which makes it biocompatible and potentially suitable for applications in the medical, pharmaceutical, cosmetic, and paint industries. The methods adopted and the nonionic surfactant used in the synthesis of calcium carbonate nanocrystalline aragonite polymorphs were environmentally friendly and can be scaled up for industrial production. The sources are naturally available materials that are by-products of the seafood industry, which offers an opportunity for exploitation in numerous industrial applications. Abdullahi Shafiu Kamba, Maznah Ismail, Tengku Azmi Tengku Ibrahim, and Zuki Abu Bakar Zakaria Copyright © 2013 Abdullahi Shafiu Kamba et al. All rights reserved.