Journal of Nanomaterials The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Preparation and Rheological Characterization of Imogolite Hydrogels Wed, 23 Jul 2014 13:48:22 +0000 Imogolite, one of the aluminium silicates, has a nanotube structure and has been known to form gel under alkaline condition. Imogolite nanotubes were synthesized in an acidic solution with various tube lengths by controlling the aging time from 1 d to 14 d. The length of the nanotubes grew from 100 nm to several μm as the aging time. Pure imogolite hydrogels were prepared by applying a salting-out method and centrifugation from its dispersed solutions with various tube lengths and solution pH. Imogolite hydrogel can be classified as the physically cross-linked one; the structure of the gel network is considered to be the entanglements and hydrogen bonding among nanotubes. The theoretical water contents of the prepared hydrogels were calculated as ∼99.7% in average. Gelation percentage significantly increased as the length of imogolite nanotubes. Whereas hydrogel prepared from 4 d aging sample showed the highest storage modulus of ∼970 Pa, it was found that the hydrogel could be prepared in the pH range from 6 to 10. The gel strength reached the highest value of 1000 Pa when the gel was prepared from the imogolite dispersed solution of pH 8. It could be explained by the surface charge variation of the imogolite. Kie Fujikura, Hirotaka Maeda, Akiko Obata, Keiichi Inukai, Katsuya Kato, and Toshihiro Kasuga Copyright © 2014 Kie Fujikura et al. All rights reserved. Performance Evaluation of 14 nm FinFET-Based 6T SRAM Cell Functionality for DC and Transient Circuit Analysis Wed, 23 Jul 2014 12:15:19 +0000 As the technology node size decreases, the number of static random-access memory (SRAM) cells on a single word line increases. The coupling capacitance will increase with the increase of the load of word line, which reduces the performance of SRAM, more obvious in the SRAM signal delay and the SRAM power usage. The main purpose of this study is to investigate the stability and evaluate the power consumption of a 14 nm gate length FinFET-based 6T SRAM cell functionality for direct current (DC) and transient circuit analysis, namely, in resistor-capacitor (RC) delay. In particular, Berkeley Short-channel IGFET Model-Common Multigate (BSIM-CMG) model is utilized. The simulation of the SRAM model is carried out in HSPICE based on 14 nm process technology. A shorted-gate (SG) mode FinFET is modeled on a silicon on insulator (SOI) substrate. It is tested in terms of functionality and stability. Then, a functional SRAM is simulated with 5 GHz square wave at the input of word line (WL). Ideal square wave and square wave with 100  RC, 5  RC, 1  RC, and 0.5  RC are asserted to the WL and the bit lines (BL&BLB) of SRAM. Voltage at node and is observed. The simulation shows that 1 RC is the minimum square wave that will store correct value in node and node . Thus, this discovery from the research can be used as a modeling platform for circuit designers to explore and improve the SRAM tolerance against RC delay. Wei Lim, Huei Chaeng Chin, Cheng Siong Lim, and Michael Loong Peng Tan Copyright © 2014 Wei Lim et al. All rights reserved. The Effects of Doping Copper and Mesoporous Structure on Photocatalytic Properties of TiO2 Wed, 23 Jul 2014 10:09:09 +0000 This paper describes a system for the synthesis of Cu-doped mesoporous TiO2 nanoparticles by a hydrothermal method at relatively low temperatures. The technique used is to dope the as-prepared mesoporous TiO2 system with copper. In this method, the copper species with the form of Cu1+, which was attributed to the reduction effect of dehydroxylation and evidenced by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), was well dispersed in the optimal concentration 1 wt.% Cu-doped mesoporous TiO2. In this as-prepared mesoporous TiO2 system, original particles with a size of approximately 20 nm are aggregated together to shapes of approximately 1100 nm, which resulted in the porous aggregate structure. More importantly, the enhancement of the photocatalytic activity was discussed as effects due to the formation of stable Cu(I) and the mesoporous structure in the Cu-doped mesoporous TiO2. Among them, Cu-doped mesoporous TiO2 shows the highest degradation rate of methyl orange (MO). In addition, the effects of initial solution pH on degradation of MO had also been investigated. As a result, the optimum values of initial solution pH were found to be 3. Yang Wang, Wubiao Duan, Bo Liu, Xidong Chen, Feihua Yang, and Jianping Guo Copyright © 2014 Yang Wang et al. All rights reserved. Magnetic Fe3O4/Ag Hybrid Nanoparticles as Surface-Enhanced Raman Scattering Substrate for Trace Analysis of Furazolidone in Fish Feeds Wed, 23 Jul 2014 07:27:17 +0000 Nanoparticles (NPs) composed of ferromagnetic and noble metal materials show dual functions of magnetic activity and local surface plasmon response and have great potential as substrates for surface-enhanced Raman scattering (SERS) in trace analysis. Easy-to-prepare superparamagnetic Fe3O4/Ag hybrid NPs were synthesized and optimized by adjusting the ratio of silver particles aggregated with APTMS-modified Fe3O4 NPs. The hybrid NPs were assembled under an external magnetic field before being used as substrate for SERS analysis. The SERS spectral features of furazolidone standard solution were clearly identified at concentrations as low as 40 ng mL−1, and furazolidone in fish feeds could be detected at 500 ng g−1. The results indicated that the Fe3O4/Ag hybrid NPs as SERS substrates had a great potential for detection of trace amount of furazolidone and other prohibited or restricted antibiotics in the animal and fish feeds. Wansong Yu, Yiqun Huang, Lu Pei, Yuxia Fan, Xiaohui Wang, and Keqiang Lai Copyright © 2014 Wansong Yu et al. All rights reserved. Facile Synthesis of Copper Oxide Nanoparticles via Electrospinning Tue, 22 Jul 2014 09:37:58 +0000 A novel approach for synthesizing copper oxide (CuO) nanoparticles (NPs) through electrospinning is reported. The approach is based on producing rough and discontinuous electrospun nanofibers from a precursor based on copper acetate salt and polyvinyl alcohol (PVA) polymer. Selectively removing the polymeric phase from the fibers produced highly rough CuO nanofibers, which were composed of NPs that are weakly held together in a one-dimensional (1D) manner. Sonication in a suitable liquid under controlled conditions completely disintegrated the nanofibers into NPs, resulting in the formation of uniform CuO NPs suspension. Aberration corrected high resolution transmission electron microscope (HRTEM) showed that the obtained NPs are highly crystalline and nearly sphere-like with a diameter of 30 to 70 nm. Thus, electrospinning, which is a low cost and industrially scalable technique, can also be employed for economic and large scale synthesis of NPs. Abdullah Khalil, Mustapha Jouiad, Marwan Khraisheh, and Raed Hashaikeh Copyright © 2014 Abdullah Khalil et al. All rights reserved. Influence of Pedestrian Trajectories on School Children Exposure to PM10 Tue, 22 Jul 2014 06:56:44 +0000 Three pedestrian trajectories are considered to study the influence of PM10 concentrations on children exposure, in a high-traffic street canyon. Two types of exposure were calculated: daily exposure for each wind condition and cumulative annual exposure considering all wind conditions. FLUENT was used to simulate the flow, turbulence, and PM10 dispersion in the street canyon. Our results indicate that exposure is influenced by the chosen walking trajectory and wind direction. When considering daily exposure, the highest value is achieved for the trajectory on the south side of the street, under westerly wind conditions, 13% higher than the baseline that assumes no traffic. The results indicate that a particular trajectory can be better for one specific wind direction but can represent the worst for a different wind direction. A difference of 3% to 13% higher exposure was achieved by choosing the best and worst trajectories. When computing cumulative annual exposure, trajectory on the north side of the street shows better results, 8.4% higher than the baseline value. Northerly and westerly winds result in the lowest and the highest exposure value for every studied trajectory. Careful selection of the best pedestrian paths can help reduce the exposure in busy street canyons. João Garcia, Rita Cerdeira, Luís Coelho, Prashant Kumar, and Maria da Graça Carvalho Copyright © 2014 João Garcia et al. All rights reserved. Influence of 1D and 2D Carbon Fillers and Their Functionalisation on Crystallisation and Thermomechanical Properties of Injection Moulded Nylon 6,6 Nanocomposites Tue, 22 Jul 2014 00:00:00 +0000 Carbon nanotubes (CNTs) and graphene were used as reinforcing fillers in nylon 6,6 in order to obtain nanocomposites by using an injection moulding process. The two differently structured nanofillers were used in their pristine or reduced form, after oxidation treatment and after amino functionalisation. Three low nanofiller contents were employed. Crystallisation behaviour and perfection of nylon 6,6 crystals were determined by differential scanning calorimetry and wide angle X-ray diffraction, respectively. Crystallinity was slightly enhanced in most samples as the content of the nanofillers was increased. The dimensionality of the materials was found to provide different interfaces and therefore different features in the nylon 6,6 crystal growth resulting in improved crystal perfection. Dynamical, mechanical analysis showed the maximum increases provided by the two nanostructures correspond to the addition of 0.1 wt.% amino functionalised CNTs, enhancing in 30% the storage modulus and the incorporation of 0.5 wt.% of graphene oxide caused an increase of 44% in this property. The latter also provided better thermal stability when compared to pure nylon 6,6 under inert conditions. The superior properties of graphene nanocomposites were attributed to the larger surface area of the two-dimensional graphene compared to the one-dimensional CNTs. Fabiola Navarro-Pardo, Ana L. Martínez-Hernández, Victor M. Castaño, José L. Rivera-Armenta, Francisco J. Medellín-Rodríguez, Gonzalo Martínez-Barrera, and Carlos Velasco-Santos Copyright © 2014 Fabiola Navarro-Pardo et al. All rights reserved. Tetraethyl Orthosilicate Coated Hydroxyapatite Powders for Lead Ions Removal from Aqueous Solutions Mon, 21 Jul 2014 12:22:16 +0000 The goal of this study was to synthetize and characterize a porous material based on tetraethyl orthosilicate (TEOS) coated hydroxyapatite (HApTh) after removal experiments of Pb2+ ions from aqueous solutions. In order to study the morphology and composition, the samples obtained after removal experiments of Pb2+ ions from aqueous solution with the initial Pb2+ ion concentrations of the aqueous solutions were 0.1 g·L−1 (HApTh-50) and 0.9 g·L−1 (HApTh-450) have been investigated by scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). Removal experiments of Pb2+ ions were carried out in aqueous solutions with controlled concentration of Pb2+. After the removal experiment of Pb2+ ions from solutions, porous hydroxyapatite nanoparticles were transformed into HApTh-50 and HApTh-450 due to the adsorption of Pb2+ ions followed by a cation exchange reaction. The obtained results show that the porous HApTh nanopowders could be used for Pb2+ ions removal from aqueous solutions. Rodica V. Ghita, Simona Liliana Iconaru, Cristina Liana Popa, Adrian Costescu, Philippe Le Coustumer, Mikael Motelica-Heino, and Carmen Steluta Ciobanu Copyright © 2014 Rodica V. Ghita et al. All rights reserved. First-Principle Study of H2 Adsorption on LaFeO3(110) Surface Mon, 21 Jul 2014 07:20:57 +0000 The adsorption of H2 molecule on LaFeO3(110) surface was studied by first-principle calculations. Based on the adsorption sites, adsorption energies, and electronic structures, it can be found that one H atom can be adsorbed on O atom and form –OH with the O atom, which is the most stable structure. One H atom can be adsorbed on one Fe atom, which makes Fe3+ turn to Fe2+. Two H atoms can form H2O molecule with O atom, which makes it possible to form oxygen vacancy on the surface. Yu-Hong Chen, Bing-Wen Zhang, Liang Yang, Mei-Ling Zhang, Cai-Rong Zhang, Long Kang, and Yong-Chun Luo Copyright © 2014 Yu-Hong Chen et al. All rights reserved. Functional Carbon Nanotube/Mesoporous Carbon/MnO2 Hybrid Network for High-Performance Supercapacitors Mon, 21 Jul 2014 07:15:16 +0000 A functional carbon nanotube/mesoporous carbon/MnO2 hybrid network has been developed successfully through a facile route. The resulting composites exhibited a high specific capacitance of 351 F/g at 1 A g−1, with intriguing charge/discharge rate performance and cycling stability due to a synergistic combination of large surface area and excellent electron-transport capabilities of MnO2 with the good conductivity of the carbon nanotube/mesoporous carbon networks. Such composite shows great potential to be used as electrodes for supercapacitors. Tao Tao, Ling Zhang, Hao Jiang, and Chunzhong Li Copyright © 2014 Tao Tao et al. All rights reserved. Hydroxyapatite-Functionalized Graphene: A New Hybrid Nanomaterial Sun, 20 Jul 2014 15:33:53 +0000 Graphene oxide sheets (GO) were functionalized with hydroxyapatite nanoparticles (nHAp) through a simple and effective hydrothermal treatment and a novel physicochemical process. Microstructure and crystallinity were investigated by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) absorption spectroscopy, and thermogravimetric analysis (TGA). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were performed to characterize the morphology of the functionalized material. The resulting novel materials combine the biocompatibility of the nHAp with the strength and physical properties of the graphene. C. Rodríguez-González, H. E. Cid-Luna, P. Salas, and V. M. Castaño Copyright © 2014 C. Rodríguez-González et al. All rights reserved. Evaluation of Osseointegration Ability of Porous Polyethylene Implant (Medpor) Treated with Chitosan Sun, 20 Jul 2014 11:40:08 +0000 Purpose. We suggest a successful and simple Medpor treated way with chitosan and evaluate more improved osseointegration ability of it than the orignal. Materials and Methods. Medpor was punched into circular shape and dipped into the chitosan gel solution. The Medpor plates soaked with chitosan were identified by the SEM images. We evaluated the growth rate of MC3T3-E1 cell using Von Kossa staining and MTT assay as in vitro experiment. And we implanted both Medpor plates into skull of domestic rabbits for in vivo experiment. We evaluated the osseointegration result with an optical microscope in postoperative 3 weeks and 6 weeks histologically. Results. The in vitro MC3T3-E1 cell growth rate on Medpor soaking with chitosan was faster than the original one in both Von Kossa staining and MTT assay. In animal test, Medpor soaking with chitosan shows more pronounced new bone than original Medpor too. Conclusion. Medpor soaking with chitosan was a successful modification. It is believed that the upgraded osseointegration ability of Medpor soaking with chitosan gives many benefits to clinicians using a Medpor implant for oral and maxillofacial reconstruction surgery. Kwang Kim, Byung-Hoon Kim, Seunggon Jung, Hong-Ju Park, Seung-Ho Ohk, Hee-Kyun Oh, and Min-Suk Kook Copyright © 2014 Kwang Kim et al. All rights reserved. AlGaN/GaN High Electron Mobility Transistors with Multi-/GaN Buffer Sun, 20 Jul 2014 09:01:59 +0000 We report the fabrication of AlGaN/GaN high electron mobility transistors with multi-/GaN buffer. Compared with conventional HEMT devices with a low-temperature GaN buffer, smaller gate and source-drain leakage current could be achieved with this new buffer design. Consequently, the electron mobility was larger for the proposed device due to the reduction of defect density and the corresponding improvement of crystalline quality as result of using the multi-/GaN buffer. P. C. Chang, K. H. Lee, Z. H. Wang, and S. J. Chang Copyright © 2014 P. C. Chang et al. All rights reserved. Development of Tandem Amorphous/Microcrystalline Silicon Thin-Film Large-Area See-Through Color Solar Panels with Reflective Layer and 4-Step Laser Scribing for Building-Integrated Photovoltaic Applications Sun, 20 Jul 2014 06:29:57 +0000 In this work, tandem amorphous/microcrystalline silicon thin-film large-area see-through color solar modules were successfully designed and developed for building-integrated photovoltaic applications. Novel and key technologies of reflective layers and 4-step laser scribing were researched, developed, and introduced into the production line to produce solar panels with various colors, such as purple, dark blue, light blue, silver, golden, orange, red wine, and coffee. The highest module power is 105 W and the highest visible light transmittance is near 20%. Chin-Yi Tsai and Chin-Yao Tsai Copyright © 2014 Chin-Yi Tsai and Chin-Yao Tsai. All rights reserved. Gold-Catalyzed Growth of Aluminium-Doped Zinc Oxide Nanorods by Sputtering Method Thu, 17 Jul 2014 08:04:55 +0000 Aluminium-doped zinc oxide (AZO) nanorods thin films were grown by RF magnetron sputtering on gold (Au) metal catalyst. The Au catalyst layers with 5, 10, and 15 nm thickness were deposited on glass substrates by sputtering method followed by annealing for 15 min at 500°C to form Au nanostructures on the glass substrate. The AZO thin films were then deposited on the Au catalyst at different deposition temperature varying from 200 to 500°C. Postdeposition annealing processes of the Au catalyst resulted in different morphologies of the Au catalyst layers depending on their thicknesses. This in turn gave different AZO morphologies which suggest that the Au catalyst layer thickness and the deposition temperature contribute to the growth mechanism of the AZO nanostructures. AZO nanorods thin films having hexagonal wurtzite structure with individual nanorods on the film surface were obtained from the samples deposited on 5 and 10 nm thick Au catalyst with the deposition temperature of 300°C. A. B. Rosli, M. M. Marbie, S. H. Herman, and M. H. Ani Copyright © 2014 A. B. Rosli et al. All rights reserved. In Vivo Imaging of Nitric Oxide by Magnetic Resonance Imaging Techniques Thu, 17 Jul 2014 07:47:53 +0000 Nitric oxide (NO) biosensors are novel tools for real-time bioimaging of tissue oxygen changes and physiological monitoring of tissue vasculature. Nitric oxide behavior further enhances its role in mapping signal transduction at the molecular level. Spectrometric electron paramagnetic resonance (EPR) and fluorometric imaging are well known techniques with the potential for in vivo bioimaging of NO. In tissues, NO is a specific target of nitrosyl compounds for chemical reaction, which provides a unique opportunity for application of newly identified NO biosensors. However, the accuracy and sensitivity of NO biosensors still need to be improved. Another potential magnetic resonance technique based on short term NO effects on proton relaxation enhancement is magnetic resonance imaging (MRI), and some NO biosensors may be used as potent imaging contrast agents for measurement of tumor size by MRI combined with fluorescent imaging. The present review provides supporting information regarding the possible use of nitrosyl compounds as NO biosensors in MRI and fluorescent bioimaging showing their measurement limitations and quantitative accuracy. These new approaches open a perspective regarding bioimaging of NO and the in vivo elucidation of NO effects by magnetic resonance techniques. Rakesh Sharma, Jeong-Won Seo, and Soonjo Kwon Copyright © 2014 Rakesh Sharma et al. All rights reserved. Electrochemical Reduction of Carbon Dioxide over CNT-Supported Nanoscale Copper Electrocatalysts Thu, 17 Jul 2014 07:46:36 +0000 This paper presents the experimental investigation of copper loaded carbon nanotubes (CNTs) electrocatalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts were synthesized by homogeneous deposition precipitation method (HDP) using urea as precipitating agent. The prepared catalysts were characterized by TEM, SEM, XRD, XPS, BET, and FTIR for their morphology and structure. Characterization results confirm the deposition of Cu nanoparticles (3–60 nm) on CNTs. Linear sweep voltammetry (LSV) and chronoamperometry (CA) were used to investigate the activity of the as-prepared catalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts reduced CO2 with high current density in the potential range 0~−3 V versus SCE (standard calomel electrode). Among all catalysts tested, 20 wt. % copper loaded CNTs showed maximum activity. Gas chromatograph with TCD was used to analyze liquid phase composition. The faradaic efficiency for methanol formation was estimated to be 38.5%. Sk. Safdar Hossain, Sleem ur Rahman, and Shakeel Ahmed Copyright © 2014 Sk. Safdar Hossain et al. All rights reserved. Effect of Sodium Carbonate Concentrations on the Formation and Mechanism of Regenerated Silk Fibroin Nanofibers by Electrospinning Wed, 16 Jul 2014 10:03:30 +0000 Degumming is the first process for the preparation of all silk-based products. In this paper, effect of sodium carbonate concentrations for silk degumming on the formation of electrospun silk fibroin nanofibers was investigated and the reason for the silk electrospinning process was explained for the first time by differences from the microstructure of regenerated silk fibroin. With increasing the sodium carbonate concentration, microstructure both in the aqueous solutions and in the electrospinning solutions transformed from nanofibrils to nanoparticles, leading to obvious changes on rheological property; electrospinning solutions with nanofibrils behaved like the native silk dope and owned remarkably higher viscosity than the solutions with nanoparticles showing very low viscosity. More interestingly, nanofibrils favored the formation of silk nanofibers with ease, and even nanofibers could be electrospun at concentration 2%. However, nanoparticles were completely unable to generate nanofibers at high spinning concentration 8%. Importance of sodium carbonate concentrations is heavily emphasized for impacting the microstructure types and further influencing the electrospinning performance of regenerated silk. Hence, sodium carbonate concentrations provide a controllable choice for the preparation of silk-based electrospun biomaterials with desired properties. Hao Dou and Baoqi Zuo Copyright © 2014 Hao Dou and Baoqi Zuo. All rights reserved. Mechanical and Thermal Stability Properties of Modified Rice Straw Fiber Blend with Polycaprolactone Composite Wed, 16 Jul 2014 09:50:11 +0000 The goal of this study was to investigate the effect of modified rice straw (ORS) on the mechanical and thermal properties of modified rice straw/polycaprolactone composites (ORS/PCL-Cs). The composites (Cs) of polycaprolactone (PCL) with ORS were successfully synthesized using the solution-casting method. The RS modified with octadecylamine (ODA) as an organic modifier. The prepared composites were characterized by using powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier transforms infrared spectroscopy (FT-IR), and mechanical properties were investigated. Composites of ORS/PCL showed superior mechanical properties due to greater compatibility of ORS with PCL. The XRD results showed that the intensity of the peaks decreased with the increase of ORS content from 1.0 to 7.0 wt.% in comparison with PCL peaks. Tensile measurement showed an increase in tensile modulus but a decrease in tensile strength and elongation at break as the ORS contents are increased from 1.0 to 7.0 wt.%; on the other hand, tensile strength was improved with the addition of 5.0 wt.% of ORS. Thermal stability was decreased with the increase of ORS contents. SEM micrograph indicated good dispersion of ORS into the matrix, and FT-IR spectroscopy showed that the interaction between PCL and ORS is physical interaction. Roshanak Khandanlou, Mansor B. Ahmad, Kamyar Shameli, Mohd Zobir Hussein, Norhazlin Zainuddin, and Katayoon Kalantari Copyright © 2014 Roshanak Khandanlou et al. All rights reserved. Porous Methyltrimethoxysilane Coated Nanoscale-Hydroxyapatite for Removing Lead Ions from Aqueous Solutions Wed, 16 Jul 2014 09:29:20 +0000 The aim of this study was to synthetize new porous nanoparticles based on methyltrimethoxysilane coated hydroxyapatite (MTHAp) for lead removal form aqueous solutions. The morphological and compositional analysis of MTHAp were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS). Removal experiments of Pb2+ ions were carried out in aqueous solutions with controlled concentration of Pb2+ at a fixed pH value of 3 and 5 respectively. After the removal experiment of Pb2+ ions from solutions, porous hydroxyapatite nanoparticles were transformed into PbMTHAp_3 and PbMTHAp_5 via the adsorption of Pb2+ ions followed by a cation exchange reaction. The X-ray diffraction spectra of PbMTHAp_3 and PbMTHAp_5 revealed that the powders, after removal of the Pb2+ ions, were a mixture of Ca2.5Pb7.5(PO4)6(OH)2, Pb2Ca4(PO4)2(SiO4), and Ca10(PO4)6(OH)2. Our results demonstrate that the porous hydroxyapatite nanoparticles can be used as an adsorbent for removing Pb2+ ions from aqueous solutions. C. S. Ciobanu, S. L. Iconaru, C. L. Popa, A. Costescu, M. Motelica-Heino, and D. Predoi Copyright © 2014 C. S. Ciobanu et al. All rights reserved. Preparation and Flame Retardant and Smoke Suppression Properties of Bamboo-Wood Hybrid Scrimber Filled with Calcium and Magnesium Nanoparticles Wed, 16 Jul 2014 07:35:49 +0000 The physical and mechanical properties of bamboo-wood hybrid scrimber filled with different loadings of nanoparticles were studied. The effects of nanoparticles on flame retardant and smoke suppression properties of bamboo-wood hybrid scrimber were studied by means of thermogravimetric analysis (TGA), cone calorimeter (CONE), and scanning electron microscope (SEM). The results showed that the physical and mechanical properties of bamboo-wood hybrid scrimber were improved by adding a moderate loading of nanoparticles; the optimal loading of nanoparticles was 10%. The heat transfer in bamboo-wood hybrid scrimber was prevented and the escaping channel of combustible gas was blocked by the uniformly filling effect of nanoparticles. The gas concentration was diluted by the noncombustible gas produced by pyrolysis of nanoparticles; the combustion chain reaction was suppressed by highly reactive free radicals produced by pyrolysis of nanoparticles. The residual mass of bamboo-wood hybrid scrimber filled with nanoparticles in thermogravimetric (TG) curve at 900 s and burned by method of cone calorimeter (CONE) at 600 s was increased compared to that of untreated one, which showed that inorganic mineral powder has the effect of catalytic charring. Bin Fu, Xingong Li, Guangming Yuan, Weimin Chen, and Yage Pan Copyright © 2014 Bin Fu et al. All rights reserved. A Review on Characterizations and Biocompatibility of Functionalized Carbon Nanotubes in Drug Delivery Design Tue, 15 Jul 2014 14:32:15 +0000 The revolutionary development of functionalized carbon nanotubes (f-CNTs) for applications in nanomedicine has emerged as one of the most interesting fields, which has increased exponentially in recent years. This is due to their appealing physical and chemical properties, as well as their unique architecture. After a brief introduction on the physicochemical properties of carbon nanotubes (CNTs), we described several functionalization methods for the surface modification of CNTs, with the aim to facilitate their solubility in physiological aqueous environment. This review focuses on recent advances in drug delivery design based on f-CNTs with an emphasis on the determination of various parameters involved and characterization methods used in order to achieve higher therapeutic efficacy of targeted drug delivery. In particular, we will highlight a variety of different analytical techniques which can be used to characterize the elemental composition, chemical structure, and functional groups introduced onto the CNTs after surface modification. We also review the current progress of available in vitro biocompatibility assays based on f-CNTs and then discuss their toxicological profile and biodistribution for advanced drug delivery. Julia M. Tan, Palanisamy Arulselvan, Sharida Fakurazi, Hairuszah Ithnin, and Mohd Zobir Hussein Copyright © 2014 Julia M. Tan et al. All rights reserved. Electromagnetic Wave Shielding Effectiveness Based on Carbon Microcoil-Polyurethane Composites Tue, 15 Jul 2014 12:04:21 +0000 Carbon microcoils (CMCs) were deposited onto Al2O3 substrates using C2H2/H2 as source gases and SF6 as an incorporated additive gas in a thermal chemical vapor deposition system. CMC-polyurethane (PU) composites were obtained by dispersing the CMCs in the PU with a dimethylformamide additive. The electromagnetic wave shielding properties of the CMC-PU composites were examined in the frequency range of 0.25–1.5 GHz. The shielding effectiveness (SE) of the CMCs-PU systematically increases with increasing the content of CMCs and/or the layer thickness. Based on these results, the main SE mechanism for this work was suggested and discussed. Gi-Hwan Kang and Sung-Hoon Kim Copyright © 2014 Gi-Hwan Kang and Sung-Hoon Kim. All rights reserved. Improved Reliability of Small Molecule Organic Solar Cells by Double Anode Buffer Layers Tue, 15 Jul 2014 09:37:33 +0000 An optimized hybrid planar heterojunction (PHJ) of small molecule organic solar cells (SM-OSCs) based on copper phthalocyanine (CuPc) as donor and fullerene (C60) as acceptor was fabricated, which obviously enhanced the performance of device by sequentially using both MoO3 and pentacene as double anode buffer layers (ABL), also known as hole extraction layer (HEL). A series of the vacuum-deposited ABL, acting as an electron and exciton blocking layer, were examined for their characteristics in SM-OSCs. The performance and reliability were compared between conventional ITO/ABL/CuPc/C60/BCP/Ag cells and the new ITO/double ABL/CuPc/C60/BCP/Ag cells. The effect on the electrical properties of these materials was also investigated to obtain the optimal thickness of ABL. The comparison shows that the modified cell has an enhanced reliability compared to traditional cells. The improvement of lifetime was attributed to the idea of double layers to prevent humidity and oxygen from diffusing into the active layer. We demonstrated that the interfacial extraction layers are necessary to avoid degradation of device. That is to say, in normal temperature and pressure, a new avenue for the device within double buffer layers has exhibited the highest values of open circuit voltage (Voc), fill factor (FF), and lifetime in this work compared to monolayer of ABL. Pao-Hsun Huang, Chien-Jung Huang, Kan-Lin Chen, Jhong-Ciao Ke, Yeong-Her Wang, and Chih-Chieh Kang Copyright © 2014 Pao-Hsun Huang et al. All rights reserved. Biological Effect of Gas Plasma Treatment on CO2 Gas Foaming/Salt Leaching Fabricated Porous Polycaprolactone Scaffolds in Bone Tissue Engineering Tue, 15 Jul 2014 07:58:15 +0000 Porous polycaprolactone (PCL) scaffolds were fabricated by using the CO2 gas foaming/salt leaching process and then PCL scaffolds surface was treated by oxygen or nitrogen gas plasma in order to enhance the cell adhesion, spreading, and proliferation. The PCL and NaCl were mixed in the ratios of 1 : 1. The supercritical CO2 gas foaming process was carried out by solubilizing CO2 within samples at 50°C and 8 MPa for 6 hr and depressurization rate was 0.4 MPa/s. The oxygen or nitrogen plasma treated porous PCL scaffolds were prepared at discharge power 100 W and 10 mTorr for 60 s. The mean pore size of porous PCL scaffolds showed 427.89 μm. The gas plasma treated porous PCL scaffolds surface showed hydrophilic property and the enhanced adhesion and proliferation of MC3T3-E1 cells comparing to untreated porous PCL scaffolds. The PCL scaffolds produced from the gas foaming/salt leaching and plasma surface treatment are suitable for potential applications in bone tissue engineering. Tae-Yeong Bak, Min-Suk Kook, Sang-Chul Jung, and Byung-Hoon Kim Copyright © 2014 Tae-Yeong Bak et al. All rights reserved. Scaffolding Biomaterials for Cartilage Regeneration Tue, 15 Jul 2014 00:00:00 +0000 Completely repairing of damaged cartilage is a difficult procedure. In recent years, the use of tissue engineering approach in which scaffolds play a vital role to regenerate cartilage has become a new research field. Investigating the advances in biological cartilage scaffolds has been regarded as the main research direction and has great significance for the construction of artificial cartilage. Native biological materials and synthetic polymeric materials have their advantages and disadvantages. The disadvantages can be overcome through either physical modification or biochemical modification. Additionally, developing composite materials, biomimetic materials, and nanomaterials can make scaffolds acquire better biocompatibility and mechanical adaptability. Zhen Cao, Ce Dou, and Shiwu Dong Copyright © 2014 Zhen Cao et al. All rights reserved. Transmissive/Reflective Structural Color Filters: Theory and Applications Tue, 15 Jul 2014 00:00:00 +0000 Structural color filters, which obtain color selection by varying structures, have attracted extensive research interest in recent years due to the advantages of compactness, stability, multifunctions, and so on. In general, the mechanisms of structural colors are based on the interaction between light and structures, including light diffraction, cavity resonance, and surface plasmon resonance. This paper reviews recent progress of various structural color techniques and the integration applications of structural color filters in CMOS image sensors, solar cells, and display. Yan Yu, Long Wen, Shichao Song, and Qin Chen Copyright © 2014 Yan Yu et al. All rights reserved. Growth and Characterization of Nanostructured TiCrN Films Prepared by DC Magnetron Cosputtering Mon, 14 Jul 2014 08:20:36 +0000 Nanostructured TiCrN films were grown on Si (100) wafers by reactive DC unbalanced magnetron cosputtering technique without external heating and voltage biasing to the substrates. The effects of Ti sputtering current on the chemical composition, chemical state, electronic structure, crystal structure, and morphology of the TiCrN films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM), respectively. The results showed that all prepared films were formed as an understoichiometric (Ti, Cr)N solid solution with the fcc B1 type phase. The films exhibited a nanostructure with a crystallite size of less than 14 nm. The deconvolution of XPS spectra revealed the chemical bonding between Ti, Cr, N, and O elements. The addition of Ti contents led to the decrease of valence electrons filled in the d conduction bands which result in the change of binding energy of electrons in core levels. The roughness of the films was found to increase with increasing . The cross-sectional morphology of the films showed columnar structure with dome tops. Chutima Paksunchai, Somyod Denchitcharoen, Surasing Chaiyakun, and Pichet Limsuwan Copyright © 2014 Chutima Paksunchai et al. All rights reserved. Recent Advances in Facile Synthesis of Bimetallic Nanostructures: An Overview Mon, 14 Jul 2014 07:36:28 +0000 Nobel metal nanomaterials with interesting physical and chemical properties are ideal building blocks for engineering and tailoring nanoscale structures for specific technological applications. Bimetallic nanomaterials consisting of magnetic metals and noble metals have attracted much interest for their promising potentials in many fields including magnetic sensors, catalysts, optical detection, and biomedical applications. Particularly, effective control of the size, shape, architecture, and compositional microstructure of metal nanomaterials plays an important role in enhancing their functionality and application potentials, for example, in fuel cells, optical and biomedical sensing. This paper focuses on recent advances in controllable synthesis of bimetallic nanostructured materials. Recent contributions in controllable synthesis of bimetallic nanomaterials with different architectures including nanoparticles, nanowires, nanosheets, or nanotubes and their assemblies are presented in this paper. A wide range of facile synthesis methods are covered herein with high emphasis on wet chemical methods owing to their facility of use, efficacy, and smaller environmental footprint. Arash Dehghan Banadaki and Amir Kajbafvala Copyright © 2014 Arash Dehghan Banadaki and Amir Kajbafvala. All rights reserved. Arc-Discharge Synthesis of Iron Encapsulated in Carbon Nanoparticles for Biomedical Applications Sun, 13 Jul 2014 12:35:12 +0000 The objective of the present work is to improve the protection against the oxidation that usually appears in core@shell nanoparticles. Spherical iron nanoparticles coated with a carbon shell were obtained by a modified arc-discharge reactor, which permits controlling the diameter of the iron core and the carbon shell of the particles. Oxidized iron nanoparticles involve a loss of the magnetic characteristics and also changes in the chemical properties. Our nanoparticles show superparamagnetic behavior and high magnetic saturation owing to the high purity α-Fe of core and to the high core sealing, provided by the carbon shell. A liquid iron precursor was injected in the plasma spot dragged by an inert gas flow. A fixed arc-discharge current of 40 A was used to secure a stable discharge, and several samples were produced at different conditions. Transmission electron microscopy indicated an iron core diameter between 5 and 9 nm. Selected area electron diffraction provided evidences of a highly crystalline and dense iron core. The magnetic properties were studied up to 5 K temperature using a superconducting quantum interference device. The results reveal a superparamagnetic behaviour, a narrow size distribution (), and an average diameter of 6 nm for nanoparticles having a blocking temperature near 40 K. S. Chaitoglou, M. Reza Sanaee, N. Aguiló-Aguayo, and E. Bertran Copyright © 2014 S. Chaitoglou et al. All rights reserved.