Journal of Nanomaterials The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Microstructure Changes of Ti-Al-C Films Deposited by Filtered Cathodic Vacuum Arc Thu, 24 Apr 2014 06:38:12 +0000 Nanocomposite Ti-Al-C films were deposited by filtered cathodic vacuum arc (FCVA) at different CH4 flows. The deposited films were characterized in terms of elemental and phase compositions, chemical bonds, and texture as a function of CH4 flow rate by XRD, XPS, HRTEM, Raman spectroscopy, and IR spectroscopy. The results show that the TiC grain size decreases from 4.2 to 2.9 nm as the CH4 flow rate increases from 30 to 80 sccm. The analysis of XPS, HRTEM, and Raman spectroscopy shows that the microstructure of deposited films turns from a TiC dominant TiC-C film to a carbon network dominant TiAl-doped a-C film structure as the CH4 flow increases from 30 sccm to 80 sccm. IR spectroscopy shows that most of the hydrogen atoms in the deposited films are bonded to the sp3-hybridized C atoms. All the composition and microstructure change can be explained by considering the plasma conditions and the effect of CH4 flow. Xianjuan Pang, Xiaoqiang Liu, and Bo Jin Copyright © 2014 Xianjuan Pang et al. All rights reserved. Nanopolycrystalline Diamond Sintered from Onion-Like Carbon Thu, 24 Apr 2014 00:00:00 +0000 The onion-like carbons (OLCs) annealed at 900–1400°C were used as raw materials to synthesize additive-free D-D type nanopolycrystalline diamond (nPCD) compacts in the industrial sintering conditions of 5.5 GPa, 1200°C, and 15 min. The results showed that the OLCs were transformed into additive-free D-D type nPCD compacts in industrial sintering conditions. The nPCD compacts contained a large number of nanotwins. The purities and performances of nPCD compacts were homogeneous in three dimensions. The purity and physical and mechanical performances of the nPCD compact (denoted as nPCD11) sintered from the OLCs annealed at 1100°C were the highest. The average Vickers hardness, density, and nanodiamond grain size of nPCD11 were 32 GPa, 2.7 g/cm3, and 12 nm. During sintering process, the graphite layers of OLCs ruptured from inside toward outside forming larger nanodiamond particles. At the same time, the OLCs bonded adjacent to OLCs forming additive-free D-D type nPCD compacts. Qin Zou, Ming-Zhi Wang, Wen Gong, Qiang-Hua Yu, Yan-Guo Li, and Yu-Cheng Zhao Copyright © 2014 Qin Zou et al. All rights reserved. A Novel Approach to the Fabrication of CdSe Quantum Dots in Aqueous Solution: Procedures for Controlling Size, Fluorescence Intensity, and Stability over Time Thu, 24 Apr 2014 00:00:00 +0000 This paper report a straightforward approach for the synthesis of CdSe quantum dots (CdSe QDs) in aqueous solution. This method, performed in homogeneous phase, affords optimal sizes and high quantum yields for each application desired. It is an a la carte procedure for the synthesis of nanoparticles aimed at their later application. By controlling the experimental conditions, CdSe QDs of sizes ranging between 2 and 6 nm can be obtained. The best results were achieved in an ice-bath thermostated at 4°C, using mercaptoacetic acid as dispersant. Under these conditions, a slow growth of quantum nanocrystals was generated and this was controlled kinetically by the hydrolysis of to generate   in situ, one of the forming species of the nanocrystal. The organic dispersant mercaptoacetate covalently binds to the Cd2+ ion, modifying the diffusion rate of the cation, and plays a key role in the stabilization of CdSe QDs. In optimum conditions, when kept in their own solution CdSe QDs remain dispersed over 4 months. The NPs obtained under optimal conditions show high fluorescence, which is a great advantage as regards their applications. The quantum efficiency is also high, owing to the formation under certain conditions of a nanoshell of Cd(OH)2, values of 60% being reached. M. J. Almendral-Parra, A. Alonso-Mateos, J. F. Boyero-Benito, S. Sánchez-Paradinas, and E. Rodríguez-Fernández Copyright © 2014 M. J. Almendral-Parra et al. All rights reserved. Light Absorption Enhancement in Organic Solar Cell by Embedding Ag Nanoparticles and Nanochains within the Active Layer Wed, 23 Apr 2014 12:00:42 +0000 We numerically investigate the light absorption enhancement of organic photovoltaic cells by embedding Ag nanoparticles and nanochains within the active layer using a finite element method. We analyze the enhancement mechanism of light absorption and systematically study the influence of factors such as the size and the period of silver nanoparticles. The result shows the localized surface plasmon resonance of the particles has a significant influence on the light absorption. Under AM1.5 illumination condition, a relative enhancement with a factor of 107.1% is observed for nanoparticles with a diameter of 30 nm and a period of 200 nm. In addition, different types of nanochain structures have been studied, and we find that, comparing to monodisperse nanoparticles, nanochain structures can further enhance the light absorption because of the stronger light harvesting in the long wavelength range of 600–800 nm. Sheng-Qing Zhu, Tong Zhang, Xin-Li Guo, Feng Shan, and Xiao-Yang Zhang Copyright © 2014 Sheng-Qing Zhu et al. All rights reserved. Unified Drain Current Model of Armchair Graphene Nanoribbons with Uniaxial Strain and Quantum Effect Wed, 23 Apr 2014 11:40:51 +0000 A unified current-voltage I-V model of uniaxial strained armchair graphene nanoribbons (AGNRs) incorporating quantum confinement effects is presented in this paper. The I-V model is enhanced by integrating both linear and saturation regions into a unified and precise model of AGNRs. The derivation originates from energy dispersion throughout the entire Brillouin zone of uniaxial strained AGNRs based on the tight-binding approximation. Our results reveal the modification of the energy band gap, carrier density, and drain current upon strain. The effects of quantum confinement were investigated in terms of the quantum capacitance calculated from the broadening density of states. The results show that quantum effect is greatly dependent on the magnitude of applied strain, gate voltage, channel length, and oxide thickness. The discrepancies between the classical calculation and quantum calculation were also measured and it has been found to be as high as 19% drive current loss due to the quantum confinement. Our finding which is in good agreement with the published data provides significant insight into the device performance of uniaxial strained AGNRs in nanoelectronic applications. EngSiew Kang and Razali Ismail Copyright © 2014 EngSiew Kang and Razali Ismail. All rights reserved. Quantitative Fractal Evaluation of Herbicide Effects on the Water-Absorbing Capacity of Superabsorbent Polymers Tue, 22 Apr 2014 13:37:24 +0000 The water absorption capacity of superabsorbent polymers (SAPs) is important for agricultural drought resistance. However, herbicides may leach into the soil and affect water absorption by damaging the SAP three-dimensional membrane structures. We used 100-mesh sieves, electron microscopy, and fractal theory to study swelling and water absorption in SAPs in the presence of three common herbicides (atrazine, alachlor, and tribenuron-methyl) at concentrations of 0.5, 1.0, and 2.0 mg/L. In the sieve experiments it was found that 2.0 mg/L atrazine reduces the capacity by 9.64–23.3% at different swelling points; no significant diminution was observed for the other herbicides or for lower atrazine concentrations. We found that the hydrogel membrane pore distributions have fractal characteristics in both deionized water and atrazine solution. The 2.0 mg/L atrazine destroyed the water-retaining polymer membrane pores and reduced the water-absorbing mass by modifying its three-dimensional membrane structure. A linear correlation was observed between the fractal analysis and the water-absorbing mass. Multifractal analysis characterized the membrane pore distribution by using the range of singularity indexes Δα (relative distinguishing range of 16.54–23.44%), which is superior to single-fractal analysis that uses the fractal dimension D (relative distinguishing range of 2.5–4.0%). Renkuan Liao, Shumei Ren, and Peiling Yang Copyright © 2014 Renkuan Liao et al. All rights reserved. Synthesis of Na-Doped Lithium Metatitanate and Its Absorption for Carbon Dioxide Tue, 22 Apr 2014 11:50:55 +0000 Na-doped lithium metatitanate (Na-doped Li2TiO3) absorbent was doped with Na2CO3 and lithium metatitanate (Li2TiO3) was prepared by a solid-state reaction method from mixture of TiO2 and Li2CO3. The Na-doped lithium metatitanate was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and surface area. Carbon dioxide absorption on Na-doped lithium metatitanate was investigated using TG-DTA. The results reveal an increase of the CO2 absorption capacity of the Na-doped materials with respect to pure Li2TiO3. XRD patterns of the doped samples suggest a limited substitution of Li by Na atoms within the Li2TiO3 structure. The results of experimental and modeling work were summarized to better understand the relationship between the sorbent microstructure and carbon dioxide absorption kinetics. Liu Zhirong, Zhang Huan, Wang Yun, and Zhan Xinxing Copyright © 2014 Liu Zhirong et al. All rights reserved. Variable Optical Attenuator Based on Long-Range Surface Plasmon Polariton Multimode Interference Coupler Tue, 22 Apr 2014 00:00:00 +0000 The fabrication and characterization of a thermal variable optical attenuator based on long-range surface plasmon polariton (LRSPP) waveguide with multimode interference architecture were investigated. The surface morphology and waveguide configuration of Au stripe were studied by atomic force microscopy. The fluctuation of refractive index of poly(methyl-methacrylate-glycidyl-methacrylate) polymer cladding was confirmed to be less than within 8 h curing at . The end-fire excitation of LRSPP mode guiding at 1550 nm along Au stripe indicated that the extinction ratio of attenuator was about 12 dB at a driving power of 69 mW. The measured optical rise time and fall time are 0.57 and 0.87 ms, respectively. These favorable properties promise potentials of this plasmonic device in the application of optical interconnection. Xiaoqiang Sun, Ying Xie, Tong Liu, Changming Chen, Fei Wang, and Daming Zhang Copyright © 2014 Xiaoqiang Sun et al. All rights reserved. Titanium Oxide Nanotube Surface Topography and MicroRNA-488 Contribute to Modulating Osteogenesis Tue, 22 Apr 2014 00:00:00 +0000 Understanding the biocomplexity of cell behavior in relation to the topographical characteristics of implants is essential for successful osseointegration with good longevity and minimum failure. Here, we investigated whether culture on titanium oxide (TiO2) nanotubes of various diameters could affect the behavior and differentiation of MC3T3-E1 cells. Among the tested nanotubes, those of 50 nm in diameter were found to trigger the expression of the osteoblast-specific transcription factors, sp7 and Dlx5, and upregulate the expression of alkaline phosphatase (ALP). Here, we report that miR-488 was significantly induced in osteoblasts cultured on 50 nm nanotubes and continued to increase with the progression of osteoblast differentiation. Furthermore, downregulation of miR-488 suppressed the expression levels of ALP and matrix metalloprotease-2 (MMP-2). This suppression of ALP transcription was overcome by treatment with the MMP-2 activator, bafilomycin A1. Collectively, these results suggest that 50 nm is the optimum TiO2 nanotube diameter for implants, and that modulation of miR-488 can change the differentiation activity of cells on TiO2 nanotubes. This emphasizes that we must fully understand the physicochemical properties of TiO2 nanotubes and the endogenous biomolecules that interact with such surfaces, in order to fully support their clinical application. Yeon-Ho Kang, Bohm Choi, Chihyun Ahn, Seunghan Oh, Myeung Soo Lee, and Eun-Jung Jin Copyright © 2014 Yeon-Ho Kang et al. All rights reserved. Modes and Carrier Density in Dispersive and Nonlinear Gain Planar Photonic Crystal Cavity Thu, 17 Apr 2014 13:58:27 +0000 The cavity mode and carrier density in dispersive and nonlinear gain planar photonic crystal cavities are studied with the three-dimensional finite-difference time-domain method. Planar photonic crystal cavity can enhance light mater interaction, which can be used to design a photonic crystal cavity laser. With the effect of both total internal reflection and photonic band gap confinement, the frequency responses of the planar photonic crystal cavity can be obtained by simulation. The effect of carrier diffusion is calculated through the laser rate equations. The electric field intensity distribution, temporal behavior of electric field energy, and carrier density characteristics are analyzed from the resonance cavity mode. Renlong Zhou, Mengxiong Wu, Yingyi Xiao, Lingxi Wu, Qiong Liu, Suxia Xie, Hui Deng, Lisan Zeng, and Guozheng Nie Copyright © 2014 Renlong Zhou et al. All rights reserved. Sm:HAp Nanopowders Present Antibacterial Activity against Enterococcus faecalis Thu, 17 Apr 2014 13:09:16 +0000 The synthesis of nanoparticles with inhibitory and bactericidal effects represents a great interest in development of new materials for biological applications. In this paper we present for the first time the synthesis of nanoparticles at low temperature and primary tests concerning the adherence of Enterococcus faecalis ATCC 29212 (gram-positive bacteria). All the XRD peaks were indexed in accordance with the hexagonal HAp in P63m space group. The EDAX spectrum and elemental mapping of O, P, Ca, and Sm demonstrate that all the elements were homogeneously distributed in with . The peaks at 347.3 eV, 532.1 eV, and 133.8 eV in the XPS spectra can be attributed to the binding energy of Ca 2p, O 1s, and P 2p. The peak at 1084.4 eV observed in was attributed to the Sm 3d5/2. Bacterial adhesion was reduced on sample when compared to pure HAp and significant differences in bacterial adhesion on pure HAp and Sm:HAp were observed. The bacterial adhesion decreased when the samarium concentrations increased. Finally, we demonstrate that the Sm:HAp nanopowder with showed high antibacterial activity against Enterococcus faecalis ATCC 29212. Carmen Steluta Ciobanu, Cristina Liana Popa, and Daniela Predoi Copyright © 2014 Carmen Steluta Ciobanu et al. All rights reserved. Tribological Performance and Lubrication Mechanism of Alkylimidazolium Dialkyl Phosphates Ionic Liquids as Lubricants for Si3N4-Ti3SiC2 Contacts Wed, 16 Apr 2014 14:15:08 +0000 The tribological performance of Si3N4-Ti3SiC2 contacts lubricated by alkylimidazolium dialkyl phosphates ionic liquids (ILs) was investigated using an Optimol SRV-IV oscillating reciprocating friction and wear tester at room temperature (25°C) and 100°C. Glycerol and tributyl phosphate (TBP) were also selected as lubricants for Si3N4-Ti3SiC2 contacts to study the tribological properties under the same experimental conditions for comparison. Results show that the alkylimidazolium dialkyl phosphates ILs were effective in reducing the friction and wear for Si3N4-Ti3SiC2contacts, and their performance is superior to that of glycerol and TBP. The SEM/EDS and XPS results reveal that the excellent tribological endurance of alkylimidazolium dialkyl phosphates ILs is mainly attributed to the high load-carrying capacity of the ILs and the formation of surface protective films consisting of TiO2, SiOx, titanium phosphate, amines, and nitrogen oxides by the tribochemical reactions. Hai-zhong Wang, Dan Qiao, Song-wei Zhang, Da-peng Feng, and Jin-jun Lu Copyright © 2014 Hai-zhong Wang et al. All rights reserved. Performance Study of CdS/Co-Doped-CdSe Quantum Dot Sensitized Solar Cells Wed, 16 Apr 2014 09:39:49 +0000 In order to optimize the charge transfer path in quantum dot sensitized solar cells (QDSCs), we employed successive ionic layer adsorption and reaction method to dope CdSe with Co for fabricating CdS/Co-doped-CdSe QDSCs constructed with CdS/Co-doped-CdSe deposited on mesoscopic TiO2 film as photoanode, Pt counter electrode, and sulfide/polysulfide electrolyte. After Co doping, the bandgap of CdSe quantum dot decreases, and the conduction band and valence band all improve, forming a cascade energy level which is more conducive to charge transport inside the solar cell and reducing the recombination of electron-hole thus improving the photocurrent and ultimately improving the power conversion efficiency. This work has not been found in the literature. Xiaoping Zou, Sheng He, Gongqing Teng, and Chuan Zhao Copyright © 2014 Xiaoping Zou et al. All rights reserved. Tribological Performance of Silahydrocarbons Used as Steel-Steel Lubricants under Vacuum and Atmospheric Pressure Wed, 16 Apr 2014 07:02:08 +0000 The silahydrocarbons of tetraalkylsilanes with different substituted alkyl groups (named as SiCH) were synthesized and evaluated as lubricants for steel-steel contacts by a home-made vacuum four-ball tribometer (VFBT-4000) under atmospheric pressure and under vacuum pressure ( Pa). The SiCH oils possess better thermal stability, low temperature fluidity, and lower saturated vapor pressure than those of multialkylatedcyclopentanes (MACs). The tribological performances of the SiCH oils are also superior to those of MACs and PFPE-Z25 in terms of friction-reduction ability and antiwear capacity under sliding friction at vacuum. The SEM/EDS and XPS results reveal that the boundary lubricating film consisting of compounds is formed by tribochemical reactions and serious adhesion wear under atmospheric pressure and the film consisting of compounds is formed on the worn surface under vacuum pressure. Hai-Zhong Wang, Song-Wei Zhang, Dan Qiao, Da-Peng Feng, and Wei-Min Liu Copyright © 2014 Hai-Zhong Wang et al. All rights reserved. Applications of Dendrimers in Drug Delivery Agents, Diagnosis, Therapy, and Detection Tue, 15 Apr 2014 16:30:48 +0000 In recent years, the application of dendrimers in biomedicine attracted much attention from scientists. Dendrimers are interesting for biomedical applications because of their characteristics, including: a hyperbranching, well-defined globular structures, excellent structural uniformity, multivalency, variable chemical composition, and high biological compatibility. In particular, the three-dimensional architecture of dendrimers can incorporate a variety of biologically active agents to form biologically active conjugates. This review of dendrimers focuses on their use as protein mimics, drug delivery agents, anticancer and antiviral therapeutics, and in biomedical diagnostic applications such as chemically modified electrodes. B. Noriega-Luna, Luis A. Godínez, Francisco J. Rodríguez, A. Rodríguez, G. Zaldívar-Lelo de Larrea, C. F. Sosa-Ferreyra, R. F. Mercado-Curiel, J. Manríquez, and E. Bustos Copyright © 2014 B. Noriega-Luna et al. All rights reserved. Efficient Photocatalytic Degradation of Rhodamine B Dye by Aligned Arrays of Self-Assembled Hydrogen Titanate Nanotubes Tue, 15 Apr 2014 14:13:44 +0000 We show that an aligned array of hydrothermally grown, multiwalled hydrogen titanate (H2Ti3O7) nanotubes—anchored to both faces of a metallic Ti foil—acts as an efficient photocatalyst. We studied the degradation of rhodamine B dye in the presence of the nanostructured photocatalyst under UV irradiation, by monitoring the optical absorption of the dye. Rhodamine B was chosen as a representative—and particularly harmful—industrial pollutant dye. The inner and outer diameters of the H2Ti3O7 nanotubes were 5 nm and 10 nm, respectively. The nanotube array catalyst is recyclable and structurally stable. Most importantly, it shows comparable or higher photodecomposition rate constant than those of both H2Ti3O7 nanotube powder and P-25 (Degussa). The enhanced photocatalytic performance may be ascribed to the nanotube array having a superhydrophilic surface with a high accessible surface area. Sriparna Chatterjee, Avesh K. Tyagi, and Pushan Ayyub Copyright © 2014 Sriparna Chatterjee et al. All rights reserved. Hydrothermal Synthesis, Characterization, and Optical Properties of Ce Doped Bi2MoO6 Nanoplates Tue, 15 Apr 2014 14:06:12 +0000 Undoped and Ce doped Bi2MoO6 samples were synthesized by hydrothermal reaction at 180°C for 20 h. Phase, morphology, atomic vibration, and optical properties were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and UV-visible spectroscopy. In this research, the products were orthorhombic Bi2MoO6 nanoplates with the growth direction along the [0b0], including the asymmetric and symmetric stretching and bending modes of Bi–O and Mo–O. Undoped and Ce doped Bi2MoO6 samples show a strong absorption in the UV region. Anukorn Phuruangrat, Nuengruethai Ekthammathat, Budsabong Kuntalue, Phattranit Dumrongrojthanath, Somchai Thongtem, and Titipun Thongtem Copyright © 2014 Anukorn Phuruangrat et al. All rights reserved. Facile Deposition of Ultrafine Silver Particles on Silicon Surface Not Submerged in Precursor Solutions for Applications in Antireflective Layer Tue, 15 Apr 2014 13:01:18 +0000 Using a facile deposition method, the ultrafine silver particles are successfully deposited on the Si surface that is not submerged in precursor solutions. The ultrafine silver particles have many advantages, such as quasiround shape, uniformity in size, monodisperse distribution, and reduction of agglomeration. The internal physical procedure in the deposition is also investigated. The results show that there are more particles on the rough Si surface due to the wetting effect of solid-liquid interface. The higher concentration of ethanol solvent can induce the increase of quantity and size of particles on Si surface not in solutions. The ultrafine particles can be used to prepare porous Si antireflective layer in solar cell applications. Bing Jiang, Meicheng Li, Dandan Song, Yingfeng Li, and Trevor Mwenya Copyright © 2014 Bing Jiang et al. All rights reserved. Adsorption of Reactive Black 5 on Synthesized Titanium Dioxide Nanoparticles: Equilibrium Isotherm and Kinetic Studies Tue, 15 Apr 2014 08:56:27 +0000 The synthesized titanium dioxide nanoparticles (TiO2-NPs) were used as adsorbent to remove reactive black 5 (RB 5) in aqueous solution. Various factors affecting adsorption of RB 5 aqueous solutions such as pH, initial concentration, contact time, dose of nanoparticles, and temperature were analyzed at fixed solid/solution ratio. Langmuir and Freundlich isotherms were used as model adsorption equilibrium data. Langmuir isotherm was found to be the most adequate model. The pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to describe the adsorption kinetics. The experimental data was fitted to pseudo-second-order kinetics. The thermodynamic parameters such as Gibbs-free energy, enthalpy, and entropy changes were determined. These parameters indicated the endothermic and spontaneity nature of the adsorption. The results demonstrated the fact that the TiO2-NPs are promising adsorbent for the removal of RB 5 from aqueous solutions. Majeed A. Shaheed and Falah H. Hussein Copyright © 2014 Majeed A. Shaheed and Falah H. Hussein. All rights reserved. Assessment of Morphology, Activity, and Infiltration of Astrocytes on Marine EPS-Imbedded Electrospun PCL Nanofiber Mon, 14 Apr 2014 13:18:17 +0000 Tissue engineering using a biomaterial including bioactive compounds has been researched as a way to restore injured neural systems. Extracellular polymeric substances (EPS) extracted from marine seaweeds have been known to produce positive effects on physiological activities in human tissues. In this study, an electrospun nanofiber containing brown seaweed EPS was proven to be a candidate biomaterial for neural tissue engineering. Glial fibrillary acidic protein (GFAP) as a specific marker protein increased in the astrocytes cultured on the polycaprolactone (PCL) nanofiber containing EPS (EPS-PCL nanofiber), compared with PCL nanofiber. The upregulation of GFAP indicates that the EPS-PCL nanofiber induced astrocyte activation, which supports physiological agents favorable to restore injured neural tissue. Astrocytes could infiltrate into the EPS-PCL nanofiber mat without toxicity, comparable to PCL nanofiber. These results imply that EPS-PCL nanofiber could be a useful biomaterial to regulate astrocyte activity at a molecular level and could be considered as a novel therapeutic material for neural tissue engineering. Seul Ki Min, Cho Rong Kim, Sung Hoon Kim, and Hwa Sung Shin Copyright © 2014 Seul Ki Min et al. All rights reserved. Nanostructural Colouration in Malaysian Plants: Lessons for Biomimetics and Biomaterials Mon, 14 Apr 2014 11:57:04 +0000 Plant tissues include leaves, flower petals, and fruits. These can provide us with variety of design inspirations. Biomimetics allows us to learn from nature and transfer the knowledge we gain from studying sophisticated and amazing biological structures, materials and processes to engineering and the arts. The microstructures of morphology and anatomy of plant tissue have potential applications in technology through bioinspired design, which can mimic the properties found in nature or use them as inspiration for alternative applications. Many applications have been developed as a result of studying physical properties of plant tissues. Structural colours, for example, have been applied in the design of thin films both with regard to single or multilayer thin film interference, scattering, and diffraction gratings. Iridescent, metallic, or greyish colouration found naturally in plants is the result of physical structures or physical effects and not pigmentation. Phenotypical appearance of plants with structural colouration in tropical Malaysia is correlated with environmental parameters such as location (shady understory rainforest, sunny conditions) and altitude (highlands, lowlands). Various examples of bioinspired technical innovations with structural colours highlight the importance of inspiration by structural colours in living nature. S. Zaleha M. Diah, Salmah B. Karman, and Ille C. Gebeshuber Copyright © 2014 S. Zaleha M. Diah et al. All rights reserved. Catalytic Hydrolysis of Ammonia Borane by Cobalt Nickel Nanoparticles Supported on Reduced Graphene Oxide for Hydrogen Generation Mon, 14 Apr 2014 11:02:00 +0000 Well dispersed magnetically recyclable bimetallic CoNi nanoparticles (NPs) supported on the reduced graphene oxide (RGO) were synthesized by one-step in situ coreduction of aqueous solution of cobalt(II) chloride, nickel (II) chloride, and graphite oxide (GO) with ammonia borane (AB) as the reducing agent under ambient condition. The CoNi/RGO NPs exhibits excellent catalytic activity with a total turnover frequency (TOF) value of 19.54 mol H2 mol catalyst−1 min−1 and a low activation energy value of 39.89 kJ mol−1 at room temperature. Additionally, the RGO supported CoNi NPs exhibit much higher catalytic activity than the monometallic and RGO-free CoNi counterparts. Moreover, the as-prepared catalysts exert satisfying durable stability and magnetically recyclability for the hydrolytic dehydrogenation of AB, which make the practical reusing application of the catalysts more convenient. The usage of the low-cost, easy-getting catalyst to realize the production of hydrogen under mild condition gives more confidence for the application of ammonia borane as a hydrogen storage material. Hence, this general method indicates that AB can be used as both a potential hydrogen storage material and an efficient reducing agent, and can be easily extended to facile preparation of other RGO-based metallic systems. Yuwen Yang, Fei Zhang, Hualan Wang, Qilu Yao, Xiangshu Chen, and Zhang-Hui Lu Copyright © 2014 Yuwen Yang et al. All rights reserved. Application of a Novel Semiconductor Catalyst, CT, in Degradation of Aromatic Pollutants in Wastewater: Phenol and Catechol Mon, 14 Apr 2014 08:29:48 +0000 Water-soluble phenol and phenolic compounds were generally removed via advanced oxidation processes. A novel semiconductor catalyst, CT, was the first-time employed in the present study to degrade phenol and catechol. The phenolic compounds (initial concentration of 88 mg L−1) were completely mineralized by the CT catalytic nanoparticles (1%) within 15 days, under acidic condition and with the presence of mild UV radiation (15 w, the emitted wavelength is 254 nm and the light intensity <26 μw/cm2). Under the same reaction condition, 1% TiO2 (mixture of rutile and anatase, nanopowder, <100 nm) and H2O2 had lower removal efficiency (phenol: <42%; catechol: <60%), whereas the control (without addition of catalysts/H2O2) only showed <12% removal. The processes of phenol/catechol removal by CT followed pseudo-zero-order kinetics. The aromatic structures absorbed the UV energy and passed to an excited state, which the CT worked on. The pollutants were adsorbed on the CT’s surface and oxidized via charge-transfer and hydroxyl radical generation by CT. Given low initial concentrations, a circumstance encountered in wastewater polishing, the current set-up should be an efficient and less energy- and chemical-consumptive treatment method. Xiao Chen, Yanling Zhang, Xuefei Zhou, Shoji Ichimura, Guoxiu Tong, Qiming Zhou, Xi Chen, Wenzhao Wang, and Yan Liang Copyright © 2014 Xiao Chen et al. All rights reserved. Nanocatalysts for Hydrogen Generation from Ammonia Borane and Hydrazine Borane Mon, 14 Apr 2014 06:48:44 +0000 Ammonia borane (denoted as AB, NH3BH3) and hydrazine borane (denoted as HB, N2H4BH3), having hydrogen content as high as 19.6 wt% and 15.4 wt%, respectively, have been considered as promising hydrogen storage materials. Particularly, the AB and HB hydrolytic dehydrogenation system can ideally release 7.8 wt% and 12.2 wt% hydrogen of the starting materials, respectively, showing their high potential for chemical hydrogen storage. A variety of nanocatalysts have been prepared for catalytic dehydrogenation from aqueous or methanolic solution of AB and HB. In this review, we survey the research progresses in nanocatalysts for hydrogen generation from the hydrolysis or methanolysis of NH3BH3 and N2H4BH3. Zhang-Hui Lu, Qilu Yao, Zhujun Zhang, Yuwen Yang, and Xiangshu Chen Copyright © 2014 Zhang-Hui Lu et al. All rights reserved. Seed-Mediated Growth of Gold Nanorods: Limits of Length to Diameter Ratio Control Mon, 14 Apr 2014 00:00:00 +0000 The effects of the seed reaction conditions on the two-step seed-mediated growth of gold nanorods and the effect of gold and reducing agent content in the growth solution were evaluated. Results indicate that the reaction conditions used to produce the seeds have a significant impact on the aspect ratio of the gold nanorods produced. Increasing the concentration of gold or the reaction temperature in the seed production step results in lower length to diameter (aspect ratio) gold rods. In addition, the amount of prepared seed added to the growth solution impacts the rod aspect ratio, with increasing amounts of seed reducing the aspect ratio. The effects of reducing agent, ascorbic acid (AA), and gold content of the growth solution on the aspect ratio of the produced rods are strongly interrelated. There exists a minimum ascorbic acid to gold concentration below which rods will not form; however, increasing the ratio above this minimum results in shorter rods being formed. Characterization of nanorod growth is performed by UV-vis-NIR spectrophotometry and transmission electron microscopy (TEM). Christopher J. Ward, Robert Tronndorf, Alicia S. Eustes, Maria L. Auad, and Edward W. Davis Copyright © 2014 Christopher J. Ward et al. All rights reserved. Optical Properties of Nanoparticles and Nanocomposites Sun, 13 Apr 2014 07:45:23 +0000 Pathik Kumbhakar, Suprakas Sinha Ray, and Andey L. Stepanov Copyright © 2014 Pathik Kumbhakar et al. All rights reserved. Morphology and Electrical Conductivity of Carbon Nanocoatings Prepared from Pyrolysed Polymers Sun, 13 Apr 2014 00:00:00 +0000 Conductive carbon nanocoatings (conductive carbon layers—CCL) were formed on -Al2O3 model support using three different polymer precursors and deposition methods. This was done in an effort to improve electrical conductivity of the material through creating the appropriate morphology of the carbon layers. The best electrical properties were obtained with use of a precursor that consisted of poly-N-vinylformamide modified with pyromellitic acid (PMA). We demonstrate that these properties originate from a specific morphology of this layer that showed nanopores (3-4 nm) capable of assuring easy pathways for ion transport in real electrode materials. The proposed, water mediated, method of carbon coating of powdered supports combines coating from solution and solid phase and is easy to scale up process. The optimal polymer carbon precursor composition was used to prepare conductive carbon nanocoatings on LiFePO4 cathode material. Charge-discharge tests clearly show that C/LiFePO4 composites obtained using poly-N-vinylformamide modified with pyromellitic acid exhibit higher rechargeable capacity and longer working time in a battery cell than standard carbon/lithium iron phosphate composites. Marcin Molenda, Michał Świętosławski, Marek Drozdek, Barbara Dudek, and Roman Dziembaj Copyright © 2014 Marcin Molenda et al. All rights reserved. Influence of Temperature on Characters of Thermoelectric Generators Based on Test Bed Sun, 13 Apr 2014 00:00:00 +0000 In order to achieve the energy recovery of the coolant heat for internal combustion engine (ICE) using the thermoelectric generation (TEG) technology, one test bed for studying the influence of temperature on the characters of thermoelectric generators was established and the relationship between the temperature and characters of thermoelectric generator was researched based on it. The results showed that the cooling effect improved with the increase of fan speed which the fan was installed in the vertical direction of the radiator, but the cooling effect had a limit speed value. And it also indicated that the forced air cooling was better than the natural convection cooling method which can effectively reduce the temperature of the cold end while it has little effect on the hot end temperature. Moreover, the Seebeck coefficient was reduced with the increase of temperature difference between the two ends of thermoelectric generator and the Seebeck coefficient was also declined with one end temperature rise when the other end temperature was constant. Zongzheng Ma, Xinli Wang, and Anjie Yang Copyright © 2014 Zongzheng Ma et al. All rights reserved. Nanomaterials for Sensor Device Applications Thu, 10 Apr 2014 09:35:38 +0000 Liang-Wen Ji, Sheng-Joue Young, Chih-Hung Hsiao, and Artde Donald Kin-Tak Lam Copyright © 2014 Liang-Wen Ji et al. All rights reserved. Terahertz Performance of a GaN-Based Planar Nanochannel Device Thu, 10 Apr 2014 09:34:32 +0000 Using a combined two-dimensional-three-dimensional (2D-3D) ensemble Monte Carlo (EMC) model, the performance of a planar nanochannel device is studied at the terahertz (THz) region. The device is based on a GaN/AlGaN heterostructure in which a two-dimensional electron gas (2DEG) forms at the interface. Simulation results reveal that, at low working frequencies, the performance of the device is almost frequency independent. However, when the working frequency is higher than 0.5 THz, obvious enhancements in the device performance have been observed. The enhancements are characterized by two resonant peaks at frequencies of about 4 THz and 8 THz. Also, the frequency-dependent performance exhibits nonmonotonicity. Further studies show that the performance enhancements can be attributed to the excitations of 2D plasma waves in the device, with the emergence of the above resonant peaks corresponding to the formation of standing plasma waves. Moreover, simulation results show that the device performance increases monotonically with signal amplitude, when the device is unbiased. However, when a DC bias is applied, the performance remains almost unchanged for large signals but is significantly enhanced for small signals. Therefore, the device performance shows a strong nonmonotonic dependence on signal amplitude, and its minimal value occurs when the signal amplitude is only about times the DC bias. K. Y. Xu, Y. N. Wang, C. J. Zheng, J. W. Xiong, and G. Wang Copyright © 2014 K. Y. Xu et al. All rights reserved.