bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Rinkalore Mixture on the Flotation of Mupine Oxidised Ores, South DRCongo
Authors: Kabamba Ghislain Tshilombo , Mukuna Christian Muteba , Kitala Kongolo 
Published: January 2010

ABSTRACTIn this study, flotation of oxidised ores rich in copper and cobalt from Mupine deposit in the Democratic Republic of Congo had been investigated. This ore contains 4.85% copper, 0.16% cobalt. The recovery of copper and cobalt was performed using flotation to increase the concentration of copper and cobalt. Flotation of the oxidized ore was performed with fatty acid type Rinkalore. Copper and cobalt present in the ore were concentrated with optimal doses of sodium silicate, Rinkalore mixture of 500 g/t, 1500 g/t respectively and optimum tall oil and pH of 23% and 9.5 respectively. The influence of Rinkalore Bioex, Rinkalore Booster Q, pH and sodium silicate on optimum operating conditions were studied. Improved performance of operating conditions was obtained with the mixture of reagents Rinkalores 10 and Booster Q. Primary feed titrating 8.70% copper and 0.31% cobalt respectively had a recovery yield of 53% and 34% respectively, and rougher concentrate titrating 8.13% copper and 0.33 % Cobalt respectively had a recovery yield of 97% and 70% respectively.
A Thermomechanical Approach to the Formation of Dark Defects in High Power Laser Diodes
Authors: Martín-Martín Alonso , Iñiguez Pilar , Jimenez Juan , Oudart Myriam , Nagle Julien 
Published: January 2010

AbstractA thermomechanical model to explain the formation of dark defects in AlGaAs high power laser bars is presented. The local heating at facet defects due to nonradiative recombination and self-absorption of photons induces thermal stresses capable of producing a local plastic deformation and subsequent degradation of the device. The output power density thresholds calculated are in agreement with the data reported in the literature for these lasers.
Current Transport Mechanisms for MSM-Photodetectors on ZnO:N Thin Films
Authors: Yen Tingfang , Haungs Alan , Kim Sung Jin , Cartwright Alexander , Anderson Wayne A. 
Published: January 2010

AbstractMetal-semiconductor-metal photodetectors (MSM-PDs) on ZnO:N thin films
deposited by radiofrequency (RF) sputtering and with post N+ ion implantation processing were fabricated using a ZnO/Si structure. A 10 times reduction in dark current was observed compared to the devices on an as-deposited ZnO thin film without ion implantation. These MSM-PDs gave performances of a photo-to-dark current ratio of 2030 and responsivity (R) = 2.7 A/W; the pulse response was a 12.3 ns rise time and 15.1 ns fall time using a femto-second pulse. Temperature-dependent current -voltage (I-V-T) characteristics of the MSM-PDs were observed and the space charge limited current (SCLC) theory was applied to determine the current transport mechanisms. In the SCLC region, J∼Vm gave m to determine the current transport mechanism and the value of m changes with temperatures and applied voltages. Current transport is governed by the ZnO structure rather than the electrodes.
Room Temperature Ferromagnetism in Al-doped/Al2O3-doped ZnO Film
Authors: Ma Yuwei , Ding Jun , Ran Min , Huang Xue Lian , Ng Chee Mang 
Published: January 2010

AbstractIn this manuscript, we study the magnetic property of Al-doped/Al2O3-doped ZnO films. We found that metallic Al-doped ZnO film shows room temperature ferromagnetism (RTFM). RTFM is correlated with the interaction of Al metallic clusters and ZnO matrix. The charge transfer has been observed between metallic Al and ZnO matrix. Therefore, RTFM in metallic Al doped ZnO may be highly probable due to charge transfer between metallic Al clusters and ZnO matrix. For Al2O3-doped ZnO film (denoted as (Zn1-x, Alx)O), RTFM was found in (Zn1-x, Alx)O film with a certain Al concentration range (16 mol%<x<50 mol%). The saturation magnetization is maximized in (Zn0.70, Al0.30)O film. The mechanism of RTFM can be explained as the interaction of ZnO nanocrystals (NCs) embedded in the amorphous phase and defects surrounding them.
Wet Chemical Etching of Zn-containing oxides and HfO2 for the fabrication of Transparent TFTs
Authors: Kim Jae-Kwan , Kim Jun Young , Han Seung-Cheol , Kwak Joon Seop , Lee Ji-Myon 
Published: January 2010

AbstractThe etch rate and surface morphology of Zn-containing oxide and HfO2 films after wet chemical etching were investigated. ZnO could be easily etched using each acid tested in this study, specifically sulfuric, formic, oxalic, and HF acids. The etch rate of IGZO was strongly dependent on the etchant used, and the highest measured etch rate (500 nm/min) was achieved using buffered oxide etchant at room temperature. The etch rate of IGZO was drastically increased when sulfuric acid at concentration greater than 1.5 molar was used. Furthermore, etching of HfO2 films by BF acid proceeded through lateral widening and merging of the initial irregular pits.
Magnetic properties of Fe-doped Zn-TiO2 rutile nanoparticles
Authors: Al-Omari Imaddin , Al-Harthi Salim H. , Al-Saadi Mubarak J. , Melghit Khaled 
Published: January 2010

AbstractNanoparticles Fe (x wt. %)-doped Zn-TiO2 rutile powders, with x between 0 an 10 wt. %, were prepared using a solution chemistry route based on the wet-gel stirring method. Using the TEM images we found that the powder samples exhibit nanorods and nanosheets with nanorods oriented in different directions and accompanied by an amorphous Zn on the surface. The average length of these nanorods is about 60 nm and they have an average diameter of 7 nm. The x-ray diffraction patterns revealed the formation of the nanocrystalline particles with the rutile phase, which is characterized by the (101) diffraction peak. The magnetic properties of the samples were studied using a vibrating sample magnetometer (VSM) in magnetic filed up to 13.5 kOe and in the temperature range of 100 K to 300 K. We found that the magnetization of the samples does not saturate in the maximum available field. The magnetization (M) at an applied magnetic field of 13.5 kOe is found to increase with increasing the Fe percentage at room temperature and at 100 K. TEM measurements and atomic-force microscopy (AFM) were used to image the samples.
AlN Periodic Multiple-layer Structures Grown by MOVPE for High Quality Buffer Layer
Authors: Kuryatkov Vladimir , Feng Wen , Pandikunta Mahesh , Rosenbladt Dana , Borisov Boris , Nikishin Sergey A , Holtz Mark 
Published: January 2010

AbstractHigh crystal quality crack-free AlN on sapphire was grown by low pressure metal organic vapor phase epitaxy (MOVPE). Growth experiments combine two recent approaches: the ammonia pulse-flow method and ammonia continuous-flow growth mode by varying the V/III ratio. The detailed aspects of MOVPE, employing the periodic multilayer approach at low, intermediate, and high temperatures are described. This method yields significant reduction of screw dislocation density and provides very smooth surface for thin AlN layers.
Formation of Antibody Microarrays on Aluminum Nitride Surface Using Patterned Organosilane Self-Assembled Monolayers
Authors: Chiu Chi-Shun , Lee Hong-Mao , Gwo Shangjr 
Published: January 2010

AbstractSurface biofunctionalization of group-III nitride semiconductors has recently attracted much interest due to their biocompatibility, nontoxicity, and long-term chemical stability under demanding physiochemical conditions for chemical and biological sensing. Among III-nitrides, aluminum nitride (AlN) and aluminum gallium nitride (AlGaN) are particularly important because they are often used as the sensing surfaces for sensors based on field-effect transistor or surface acoustic wave sensor structures. Patterned self-assembled monolayer (SAM) templates are composed of two types of organosilane molecules terminated with different functional groups (amino and methyl), which were fabricated on AlN/sapphire substrates by combining photolithography, lift-off process, and self-assembly technique. Clear imaging contrast of SAM micropatterns can be observed by field emission scanning electron microscopy (FE-SEM) operating at a low accelerating voltage in the range of 0.5–1.5 kV. In this work, the formation of green fluorescent protein (GFP) antibody microarrays was demonstrated by the specific protein binding of enhanced GFP (EGFP) labeling. The observed strong fluorescent signal from antibody functionalized regions on the SAM-patterned AlN surface indicates the retained biological activity of specific molecular recognition resulting from the antibody–EGFP interaction. The results reported here show that micropatterning of organosilane SAMs by the combination of photolithographic process and lift-off technique is a practical approach for the fabrication of reaction regions on AlN-based bioanalytical microdevices.
Influence of Hydrogen on Growth of Carbon Nanotubes
Authors: Belov Maxim , Knizhnik Andrey , Lebedeva Irina , Gavrikov Alexey , Potapkin Boris , Sommerer Timothy , Eastman Chris 
Published: January 2010

AbstractThe influence of hydrogen on the growth of carbon nanostructures in thermal chemical vapor deposition is studied using density functional theory calculations. It is shown that hydrogen adatoms effectively bind to edges of graphitic structures on the Ni (111) surface. This is found to result in a significant decrease of the rate of carbon attachment to the growing graphitic structures. However, it is also demonstrated that the edges of graphitic structures which are attached to steps on the Ni surface should not be hydrogenated.
Enhanced long-term stability of functionalized silicon nanoparticles using esters
Authors: Gupta Anoop , Kluge Sebastian , Schulz Christof , Wiggers Hartmut 
Published: January 2010

AbstractThe surface of freshly etched silicon nanoparticles (Si-NPs) was covalently bonded with alkyl groups and esters via thermally induced hydrosilylation. The surface chemistry of functionalized Si-NPs was analyzed at different air exposure time by means of Fourier transform infrared spectroscopy (FTIR). We observed that the stability of functionalized Si-NPs significantly depends on the type of organic ligands attached to their surface. Ester-terminated Si-NPs exhibit higher stability compared to that are bonded with alkyl groups. We show that the use of esters with large spatial configuration causes a lower surface coverage of Si-NPs but at the same time offers better protection against surface oxidation.
Preparation of Conductive Color Powders
Authors: Weng Chin-Cheng , Cheng I-Jein , Wu Ching-Mao , Lin Yu-Chin , Huang Kuo-Tung 
Published: January 2010

AbstractIn this paper, we report that the experimental procedures for the preparation of conductive color powders that were aggregated from color pigment and conductive materials. We first modified the pigment and make the particles surface to have charges (ex: positive) and modified another conductive materials like ITO、Au、Ag particles or conductive polymer to be opposite charges (ex: negative). Then these two kinds of charge particles will aggregate in appropriate processing by static electricity and form a powder. After annealing treatment, the conductive color powder with ITO particles reveals good thermal stability and lower surface resistivity.
Key Role of Aspect Ratio in Optimising Local Surface Plasmon Sensitivities of Solution Phase Triangular Silver Nanoplates
Authors: Charles Denise E. , Aherne Damian , Ledwith Deirdre M. , Gun'ko Yurii K , Kelly John M , Blau Werner J , Brennan-Fournet Margaret E 
Published: January 2010

AbstractSolution phase triangular silver nanoplate (TSNP) ensembles are herein presented as tunable, highly sensitive, LSPR sensors with excellent potential for versatile amply responsive biosensing applications. The recorded LSPR refractive index sensitivities for the highest aspect ratio TSNPs examined are amongst the highest reported to date for various other nanostructures. Calculations demonstrate that sensitivities of the TSNP sols, as high as the theoretical upper limit, are achievable by tuning the aspect ratio parameter, without any significant diminution observed due to ensemble averaging. Theoretical studies identify the aspect ratio of the nanoplates as a key parameter in controlling the LSPR sensitivity of the TSNPs.
Monodisperse Pt-Cu Nanocubes：Synthesis, Characterization, and Electrochemical Properties
Authors: Xu Dan , Yang Hongzhou , Zou Shouzhong , Fang Jiye 
Published: January 2010

AbstractHigh-quality Pt-Cu nanocubes were prepared through simultaneous reduction of platinum (II) acetylacetonate and copper II) acetylacetonate in 1-octadecene by 1,2–tetradecanediol in the presence of tetraoctylammonium bromide, oleylamine, and 1-dodecanethiol. The growth process of Pt-Cu nanocubes was explored based on the observation of intermediates. The electrocatalytic behavior indicates that cubic Pt-Cu nanocrystals are more active than spherical Pt-Cu nanocrystals and Pt nanocrystals towards methanol oxidation reaction.
Catalytic Performance of Nanostructured Plate-type Cu and Cu-Fe on ZnO Nanorods for Steam Reforming of Methanol
Authors: Li Chien-Cheng , Lin Ran-Jin , Chen Li-Chyong , Chen Kuei-Hsien 
Published: January 2010

AbstractThe Cu-type and (Cu-Fe)-type film catalysts have been successfully prepared by the electroless plating on ZnO nanorods/stainless steel substrates. The microstructure features of the (Cu-Fe)-type films are high porosity and plate-type grains. The addition of iron into Cu-type film can improve the reducibility and the stability of the film catalysts. The reduction temperature of the (Cu-Fe)-type film catalysts decreases with increasing the addition of Fe. For Cu-5 at% Fe film, the reduction temperature is in the range of 195°C to 216°C as comparison in the range of 208°C to 233°C of the Cu-type film catalysts.
Tailored Mesoporous Silicas: From Confinement Effects to Catalysis
Authors: Buchanan, III A. C. , Kidder Michelle K. 
Published: January 2010

AbstractOrdered mesoporous silicas continue to find widespread use as supports for diverse applications such as catalysis, separations, and sensors. They provide a versatile platform for these studies because of their high surface area and the ability to control pore size, topology, and surface properties over wide ranges. Furthermore, there is a diverse array of synthetic methodologies for tailoring the pore surface with organic, organometallic, and inorganic functional groups. In this paper, we will discuss two examples of tailored mesoporous silicas and the resultant impact on chemical reactivity. First, we explore the impact of pore confinement on the thermochemical reactivity of phenethyl phenyl ether (PhCH2CH2OPh, PPE), which is a model of the dominant β-aryl ether linkage present in lignin derived from woody biomass. The influence of PPE surface immobilization, grafting density, silica pore diameter, and presence of a second surface-grafted inert “spacer” molecule on the product selectivity has been examined. We will show that the product selectivity can be substantially altered compared with the inherent gas-phase selectivity. Second, we have recently initiated an investigation of mesoporous silica supported, heterobimetallic oxide materials for photocatalytic conversion of carbon dioxide. Through surface organometallic chemistry, isolated M-O-M’ species can be generated on mesoporous silicas that, upon irradiation, form metal to metal charge transfer bands capable of converting CO2 into CO. Initial results from studies of Ti(IV)-O-Sn(II) on SBA-15 will be presented.
Increasing the Photocatalytic Activity by Mechano-chemically Milling on Zn- Doped TiO2
Authors: Li Chennan , Srinivasan Sesha , Algarin Paula , Kislov Nikolai , Phani Ayala , Stefanakos Lee , Goswami Yogi 
Published: January 2010

AbstractThis paper pursed one new cost effective strategy to improve the photocatalytic activity of the sol-gel developed Zn doped TiO2 by mechano-chemically milling in high energy planetary mill. The results showed that the photocatlytic activity was improved two times due to the increase of the surface area and the decrease in average crystallite size at the same time after using the high energy ball milling. Kubelka-Munk spectra of pristine and ball milled samples revealed a blue shift from 3.2 eV to 3.35 eV, which may be because of the presence of quantum size effects. SEM microstructural investigations revealed variations in the surface morphology with different Zn doping concentrations in the TiO2-Xwt.% Zn nanoparticulates. EDS spectra of these samples confirmed the stoichiometric concentration of Zn. Other characterization including X-ray diffraction (XRD), BET surface and the photocatalytic decomposition were also studied and the results were in agreement with each other.
Fabricating Nanocomposite Catalysts through Interfacial Fusion of Metallic Nanoparticles
Authors: Choi Yong-Jae , Chen Tsan-Yao , Chiu Chi-Kai , Luo Tzy-Jiun Mark 
Published: January 2010

AbstractFusion of metallic nanoparticles at both surfaces of silica colloids and nanoporous bulk materials has been utilized as an effective method to integrate inorganic and organic components into nanocomposite materials. When performed on substrates that have been modified with hydrophobic functional groups, aminosilica colloids doped with metallic nanoparticles through the ethylenediamine functional groups adhere to the substrates and self-assemble into nanocomposite film with its thickness to be the function of the time. On the contrary, without metal-bound functional groups, fusion of metallic nanoparticles can be induced at the interface of nanoporous silica when polymer is utilized as the mobile phase for metal nanoparticles inside of silica. Formation, mobilization, and fusion of metallic nanoparticles within the polymer phase can be simultaneously induced at 160 ˚C, during which reactions alter the physical appearance of the materials from transparent to silver metallic color. These two methods can combine with soft-lithography method to create functional structures that exhibit enhanced electrochemical property.
Single Step Morphology-controlled Synthesis of Silver Nanoparticles
Authors: Etacheri Vinodkumar , Georgekutty Reenamole , Seery Michael K , Pillai Suresh C 
Published: January 2010

AbstractSilver nanoparticles having different size and plasmon resonances were synthesized through a single step aqueous based method. The current procedure was based on the reduction of silver ions by ascorbic acid in the presence of sodiumborohydride and trisodium citrate. Triangular colloidal nanoparticles having different plasmon resonances (and hence different size and colours) were synthesized by varying only the concentration of ascorbic acid. These nanoparticles were found to be stable without using any surfactants or polymers. This study revealed a strong correlation between particle growth and concentration of constituent chemicals. Crystallinity and phase purity of the silver samples were investigated through powder X-ray diffraction studies (XRD). Absorption spectra of various silver particles were recorded using UV/Vis/NIR spectrometer. Morphological analysis was performed using transmission electron microscopy (TEM) and average edge lengths of nanoparticles were also calculated.
Synthesis and catalytic application of ceria nanoparticles and ceria-SiC composites
Authors: Schrage Christian , Kockrick Emanuel , Kaskel Stefan 
Published: January 2010

AbstractThe synthesis of ceria nanoparticles using an inverse microemulsion technique and precipitation method was investigated. Ceria nanoparticles were synthesized by adding diluted ammonia to a microemulsion consisting of n-heptane, Marlophen NP5 and cerium nitrate. The micelle and particle size were adjustable in the range of 5-12nm by varying the molar ratio of water to surfactant and analyzed by dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and high-resolution transmission electron microscopy (HRTEM). After isolation through precipitation, the nanoparticles were subsequently treated at 100-600 °C. The catalytic activity of particles annealed at 400 and 600 °C were tested in soot combustion reactions and characterized by temperature-programmed oxidation (TPO) indicating a size-dependant activity. To prevent the nanoparticles from aggregation, the microemulsion technique was adopted to integrate the nanoparticles homogeneously into a mesoporous SiC matrix through the use of a preceramic polymer. The obtained composite material was also tested in soot combustion reactions.
Development of Switchable “Smart” Biomaterials Using an Environmental Friendly Technology
Authors: Barroso Telma , Viveiros Raquel , Costa Eunice , Temtem Márcio , Casimiro Teresa , Aguiar-Ricardo Ana 
Published: January 2010

AbstractThe possibility of using three dimensional porous networks as microreactors for synthesizing thermoresponsive polymers and hydrogels in a CO2 environment is an important breakthrough in the strategies to prepare smart films, membranes and porous bulky devices that undergo fast reversible changes in surface properties triggered by external stimuli. In situ synthesis of thermoresponsive polymers namely, poly(N-isopropylacrylamide) (PNIPAAm) and poly (N,N-diethylacrylamide) (PDEAAm) within chitosan (CHT), collagen (CLG) and chitosan-collagen (CHT:CLG) blended scaffolds were performed in order to further impregnate with model drugs. The performance of these switchable release devices was evaluated through the study of drug release kinetics as a function of temperature and pH. The same methodology was successfully applied to produce thermoresponsive polysulfone-based membranes.
Controllable Mesopore-size and Outer Diameter of Silica Nanoparticles Prepared by a Novel Water/Oil-Phase Technique
Authors: Nandiyanto Asep Bayu Dani , Kaihatsu Yutaka , Iskandar Ferry , Okuyama Kikuo 
Published: January 2010

AbstractTunable pore size and outer particle diameter of spherical mesoporous silica particles in the nanometer range were successfully synthesized using a novel water/oil-phase synthesis technique. This method involves (i) simultaneous hydrolytic condensation of tetraorthosilicate to form silica and polymerization of styrene into polystyrene (PS), (ii) self-assembly nanocluster silica and nanocluster PS to form silica/PSL nanoparticle, and (iii) calcination process to remove organic components and to produce mesoporous silica particle. In this study, an amino acid (e.g. lysine) was utilized to catalyze and to maintain the silica formation due to its ability in covering prepared silica after reaction. Further, another advantage of this catalyst is more harmless than other catalysts (e.g. ammonia, N2H4). The result showed spherical particles with controllable pore size (from 4 to 15 nm) and outer diameter (from 20 to 80 nm) was produced. The ability to control pore size and outer diameter was drastically altered by adjusting the concentration of styrene and hydrophobic molecules, respectively. After the preparation of particle was understood clearly, the large-molecule-adsorption performance of the prepared porous particles was conducted. As expected, relatively large organic molecules (i.e. Rhodamine B) were well-absorbed in the prepared sample but not by the commercial non-porous particles. With this reason, the prepared mesoporous silica particles may be used efficiently in various applications, including electronic devices, sensors, pharmaceuticals, and environmentally sensitive pursuits, due to its harmless process, compatibility for bio-application, and excellent adsorption properties.