bluuebunny/crossref_metadata_2025_split huggingface dataset:
Systematic Study of Work Functions of Single-walled Carbon Nanotubes
Authors: Kato Koichiro , Saito Susumu 
Published: February 2010

AbstractThe work function is one of the crucial quantities in understanding their field emission properties and applying carbon nanotubes to electronic devices. We perform the systematic study of work functions of 44 kinds of isolated single-walled carbon nanotubes in the framework of the density functional theory. It has been revealed that the first-principles study plays a very important role for predicting various properties of carbon nanotubes. In general, we have to perform the structural relaxation in order to know the accurate electronic properties of carbon nanotubes. Therefore we carry out the complete geometrical relaxations for 44 kinds of carbon nanotubes and evaluate their work functions. The diameters (D) of nanotubes studied satisfy 0.3 < D < 2.0 nm. Especially, we focus on the small diameter carbon nanotubes. We determine the values of work functions from the difference between the Fermi level and the vacuum level. In the semiconducting carbon nanotubes, the Fermi level is chosen at the midgap. As a result, it is found that the carbon nanotubes should be classified into three classes according to the diameter and chiral-angle dependences of work functions.
Field Emission Response from Multiwall Carbon Nanotubes Grown on Different Metallic Substrates
Authors: Lahiri Indranil , Seelaboyina Raghunandan , Choi Wonbong 
Published: February 2010

AbstractCarbon nanotubes (CNT) have seen a wide variety of applications, spread well beyond the semiconductor industries - especially in field emission related devices. For its widest possible application, it has become very much important to grow CNTs on a variety of metallic substrates and understand their field emission response. In the present study, multiwall CNTs (MWCNT), grown on pure metallic substrates like Cu, Al and W, were subjected to field emission tests under DC and AC bias. Choice of diffusion barrier layer and catalyst was also varied, to verify their effects on the emission response. Field emission behaviors from all such structures were compared with MWCNTs grown on Si. It was found that the MWCNTs grown on pure Cu substrate showed excellent field electron emission response, in terms of low turn-on field, high emission current, long time stability and very high field enhancement factor.
Carbon Nanotube Assisted Electrical Treeing for Vascular Network Synthesis
Authors: Behler Kristopher D. , Wetzel Eric D. 
Published: February 2010

AbstractElectrical treeing (ET) is a stepwise dielectric breakdown process that generates a branched, hollow network of tubules in the dielectric between the electrode and ground. In this study, the controlled growth of electrical trees (ETs) in epoxies is demonstrated as a technique for fabricating synthetic vascular systems in engineering materials. A number of experimental conditions are explored, including AC versus DC voltage and geometric arrangement of the electrode and ground. AC growth tends to induce highly branched, “bush-like” trees while DC growth tends to produce lower-order branched structures. In addition, treating electrode surfaces with multi-walled carbon nanotubes (MWCNTs) is shown to promote ET initiation, most likely due to enhancements in the local electric field intensity. The utility of these structures for vascular applications is demonstrated by filling the channels with dyed liquids.
The Effect of Reaction Driving Force on Copper Nanoparticle Preparation by Liquid Phase Reduction Method
Authors: Liu Qingming , Zhou Debi , Nishio Kazuaki , Salman Salah , Ichino Ryoichi , Okido Masazumi 
Published: February 2010

AbstractCopper nanoparticle was prepared by liquid phase reduction technique. Cu2+ was reduced to copper particle by adopting different types of reductants. Ascorbic acid (C6H8O6), phosphinic acid (H3PO2), titanium sulfate (Ti2(SO4)3) and sodium borohydride (NaBH4) were chosen as reductant, respectively. The effect of reaction driving force upon the average size of copper particle was investigated in the paper. It can be concluded that there is a firm relationship between the reaction driving force and the average size of copper particle. The average size of copper particle decreases with the increasing of reaction driving force.
Core/Shell Composite of Self-Assembled Hierarchical Bismuth Oxide/Europium Doped Gadolinium Oxide for Scintillating Detection
Authors: Tseng Teng-Kuan , Choi Jihun , Davidson Mark , Holloway Paul H 
Published: February 2010

AbstractA novel three dimensional (3D) self-assembled hierarchical bismuth oxide was prepared via a sol-gel synthesis with the aid of capping agent of polyethylene glycol-8000 (PEG-8000) at 85 ℃ in 45 min. The morphology evolution was studied versus reaction time and interpreted in terms of growth mechanisms. The as-grown 3D hierarchical flower-like bismuth oxide was crystalline cubic gamma-phase. The morphology and crystal phase of these 3D cubic gamma-phase bismuth oxide flowers were not changed with heating up to 600 ℃. The flower-like morphology was attributed to modification of the growth kinetics by the capping agent from the PEG-OH bond bridging with bismuth ions. Europium doped gadolinium oxide shell were further deposited on the bismuth oxide cores through sol-gel synthesis showing good photoluminescence characteristics at 610 and 622 nm under the excitation at 280 nm.
Fabrication of the Cerium Oxide Nanocrystal Film with Heterogeneous Ligand Structures
Authors: Hojo Daisuke , Togashi Takanari , Adschiri Tadafumi 
Published: February 2010

AbstractSufficiently dense films of cerium oxide nanocrystals modified with decanoic acid, with sizes of ˜9 nm, were fabricated on the surface by modifying a silicon substrate with 3,4-dihydroxyhydrocinnamic acid, where catechol group lied at the top. By doing this, no further pretreatment for the modified cerium oxide nanocrystals is required to fix them chemically on the substrate. Selective adhesion between nanocyrstals and the substrate for the two-dimensional assembly can be attributed to the chemical bonding formed by on-site ligand exchange between carboxyl and catechol groups.
Inter-molecular Electronic Transfer
Authors: Král Karel , Menšík Miroslav 
Published: February 2010

AbstractThe transport of electric charge is an important phenomenon in the systems like interacting quantum dots and molecules, and in polymers, including DNA molecules. We expect that in these nanostructure systems the key role is played by the interaction of the charge carriers with the optical phonons. We show the role of the multiple scattering of the charge carriers on the optical phonons in the inter-molecular transfer. The charge carrier transport based on this mechanism will be discussed theoretically and compared with the earlier experimental results on the charge transport in molecular Donor-Acceptor charge transfer crystals and also in other systems. In order to treat theoretically the electron transfer between two zero-dimensional nanostructures, we will use the model of two interacting quantum dots coupled by the electron inter-dot tunneling mechanism. A connection with the popular Marcus semiclassical charge transfer theory between molecules is also shown. We will use the nonequilibrium quantum electronic transport theory based on the nonequilibrium Green's functions.
Fabrication of Two Dimensional Array of Silica Nanospheres on GaN Using Spin Coating Method and Nomarski Image Processing
Authors: Lee Kyoungnae , yalamanchili hyma , Dawson J. M. , Korakakis D 
Published: February 2010

AbstractLarge-scale two dimensional ordering of silica nanospheres on GaN substrates was fabricated using spin-coating and observed using Matlab-based Nomarski image processing, which was developed to calculate the surface coverage of 2D and 3D ordering of silica nanospheres on GaN substrates. Optimal spin coating condition and SDS concentration were investigated with Nomarski image processing and an SEM. The details on spin coating process parameters or SDS concentration vs. surface coverage of silica nanospheres on GaN substrate are discussed, along with a theoretical exploration of the effects of nanosphere patterning on photonic crystals fabricated using this method.
Effect of Doping on the Structural and Optical Properties of Microwave-Assisted Synthesis of ZnSe@ZnS Core-Shell Quantum Dots
Authors: Bailon-Ruiz Sonia J , Perales-Perez Oscar , Singh Surinder P , Voyles Paul M 
Published: February 2010

AbstractPure and Cu-doped quantum dots of ZnSe@ZnS were synthesized in aqueous phase using microwave irradiation at 140 °C. X-ray diffraction analyses suggested the development of a ZnSe-ZnS structure. UV-vis measurements evidenced that the presence of Cu species in quantum dots caused the blue shift of exciton peaks with respect to pure, i.e. non doped ones. Photoluminescence spectra of quantum dots synthesized at Zn/Cu mole ratios of 1/0.001 and 1/0.005 exhibited a very strong emission peak centered on ˜ 515 nm. On the contrary, a weak emission peak was observed at 412 nm in pure ZnSe@ZnS quantum dots. The observed emission at 515 nm was attributed to the internal doping of Cu species, which should have induced d-d transitions in the host lattice. Quenching of the luminescence at 515 nm was observed for nominal Cu concentrations above 0.005 mM.
Synthesis and Properties of Monometallic and Bimetallic Silver and Gold Nanoparticles
Authors: Guerrero Dib Xavier Enrique , Ortiz-Méndez Ubaldo , Sepúlveda-Guzmán Selene , Kharisova Oxana Vasilievna , Ferrer Domingo , José-Yacamán Miguel 
Published: February 2010

AbstractSynthesis of Au, Ag monometallic, and Au-Ag bimetallic nanoparticles have been synthesized by successive reduction of metal salts with ascorbic acid on prefabricated seeds in the presence of cetyltrimethylammonium bromide (C16H33)N(CH3)3Br (CTAB), as a cationic surfactant, is presented in this paper. This coverage method for the prefabricated seeds is uniform, although in some cases deviations from a spherical shape are observed with the formation of nanorods or nanoprisms. Results using high-resolution STEM-XEDS elemental mapping suggest that the actual distribution of the two metals within the multilayer spheres may involve partial alloying of the metals.
Injection of spin polarized electrons in InAs quantum dots
Authors: Russ Andreas , Yasar Mesut , Petrou Athos , Kioseoglou George , Li Connie , Hanbicki Aubrey , Jonker Berend , Korkusinski Marek , Hawrylak Pawel 
Published: February 2010

AbstractWe present the results of an electrical injection study of spin polarized electrons from ferromagnetic Fe contacts into electronic shells of self-assembled InAs quantum dots (QDs) incorporated in GaAs/AlGaAs spin LED structures. The circular polarization of the emitted light was measured as function of current and magnetic field. The polarization of the EL spectra exhibits strong maxima at energies that do not coincide with the electroluminescence (EL) intensity peaks. The magnetic field dependence of the polarization maxima is consistent with spin injection from the ferromagnetic Fe contacts. The experimental results are compared with calculated emission spectra from multi-exciton complexes (N = 2 and N = 6) as function of electron spin polarization. The energies of the EL features as well as their polarization characteristics are understood in terms of energy shifts due to exchange interactions between spin-down electrons occupying adjacent shells.
Optical Properties of Si Quantum Dots in Silica via an Implantation Mask
Authors: Barbagiovanni Eric G. , Goncharova Lyudmila V , Simpson Peter J , Armstrong Nathan 
Published: February 2010

AbstractWe studied photoluminescent properties and luminescent decay dynamics in Si quantum dots (QDs) produced by Si implantation in SiO2, and their modification by the application of an implantation mask. Silicon quantum dots were prepared by ion implantation, followed by high temperature annealing leading to nanocrystal nucleation and growth. The mask was prepared by spin-coating silica microspheres to achieve laterally-selective implantation, to control QD size and separation. Transmission electron microscopy (TEM) images were obtained to verify the diameter of the quantum dots. We observe a noticeable peak shift and narrowing in the photoluminescence spectra with the application of the implantation mask. Observed maxima in the photoluminescence spectra are compared with a quantum field theoretical model using an infinite confining 1D potential for Si quantum dots. We comment on the role of excitation transfer by observing a change in the dispersion exponent of the luminescent decay dynamics due to the mask.
Theromophotovoltaic Enhancement: 2D Photonic Crystals to Increase TPV Efficiencies
Authors: Shemelya Corey M. , Vandervelde Thomas E. 
Published: February 2010

AbstractHere, we report on the enhancement of photon conversion by integration of photonic crystal (PhC) and surface plasmon (SP) structures into thermophotovoltaic (TPV) cells. PhCs consisting of rods of air are incorporated into the base of semiconductor TPV cells to increase the duration of thermal photon absorption, thus significantly enhancing quantum and conversion efficiencies (QE and CE, respectively). The potential of PhCs to augment the CE of TPV cells for most IR wavelengths makes it a widely useful technology. The ability to turn waste heat into usable energy will improve efficiency in a variety of electrical and electromechanical systems.
Surfaces Matter
Authors: Bruner Eric L. 
Published: February 2010

AbstractAculon, Inc. specializes in inventing and commercializing unique molecular-scale surface and interfacial coatings leveraging nanotechnology discoveries made at Princeton University. These coatings can be classified into three functional areas; non-stick, pro-stick/adhesion, and anti-corrosion.
The company has formulated coating solutions and processes for numerous markets including optical, display, electronics, consumer products and industrial coatings. These specialized coatings outperform all known alternatives in characteristics such as adhesion, stain resistance, and scratch resistance.
Fueling the company’s commercialization efforts are its proprietary Self-Assembled Monolayer of Phosphonates (SAMP) technology. The commercialization of SAMP treatments can be used for a variety of applications including imparting hydrophobicity, adhesion, or corrosion inhibition to numerous substrates.
For surface treatments to be effective, they must be mechanically and chemically stable under conditions experienced in the intended area of use. Aculon’s proprietary Self-Assembled Monolayer of Phosphonates methodology can impart any of these properties as desired to metals, metal oxides and even some polymer surfaces by drawing on its library of structurally tailored phosphonic acids.
The secret to the commercialization is covalent bonding, which creates a uniquely strong attachment between the SAMP and the substrate. Because the SAMP is one approximately 1.5 nm thick, it completely covers the material to which it is applied, and assures total surface coverage regardless of the type or texture of that material. The composition of the SAMP determines the properties that it imparts to its substrate.
In 1998, Professor Jeffery Schwartz of Princeton University discovered that well-ordered monolayers of phosphonates could be formed by self-assembly on a wide variety of oxide and oxide-terminated surfaces. At that time Professor Schwartz and his team also discovered that a simple dip process enabled SAMP formation on substrates of complex structures and geometries, as well as traditionally “unreactive” surfaces.
The research showed that SAMP adhesion to oxides was mechanically strong and resisted removal by hydrolysis and oxidation. It showed further that by using the dip method, SAMPs of a variety of molecular structures, including aliphatic, aromatic, and heteroaromatic, could be prepared.
Commercialization of SAMPs proves that such surface-bound phosphonates can dictate control of the surface properties of myriad substrates and that they can be implemented using well-known industrial techniques and conditions. These processes can be scaled to meet the needs of large or small facilities, and can be applied to surfaces of nearly any size or shape without special needs. Based on the needs of the producer, surface modification can be completed during the time of manufacturing or can be performed as a post-production step.
Bridging the Nano-gap: From Scientific Discovery to Real World Products
Authors: Dutta Partha Sarathi 
Published: February 2010

AbstractGoing from a small scale laboratory invention or discovery to a large scale application is not a trivial task and incorporating them into a product for a viable business is even more difficult. As technologies approach final products and applications, the number of criteria it must meet increases exponentially. Economics of the manufacturing process, environmental issues, intellectual property management, etc. needs to be assessed and monitored carefully. Bridging the gap from research to business not only needs multi-disciplinary understanding of the various aspects of the technology, but also how and what it could potentially enable or replace in current technologies and how to go about it through partnerships with global business entities. Especially with new materials, such as nano-scale materials, technology push needs to be rigorous and often the end results are uncertain. One needs to start from a large number of end user applications and narrow down to 1-2 high value-add or high volume opportunities. This process also requires constant development of the existing products to meet the exact needs for the high opportunity end markets. Timing for such efforts is crucial and the resources needed for such activities are often under-estimated by small start-up firms. Even for materials with well understood end products and established markets, significant market pull requires huge investments in product reliability demonstrations, cost of manufacturing, etc. Innovation, flexibility, change, educated risk, adaptability, focus and excellence are all key drivers and necessary ingredients for a successful and sustainable start-up venture. While scientific and engineering innovations are absolutely necessary, the metric for success for any business is revenue generation. Finding the right mechanisms for closing this gap (so-called the valley of death) is where the innovations of entrepreneurs lies. In this paper, I will share some of my personal learning experiences through the start-up company Applied Nanoworks Inc., (now Auterra Inc.).
Decreased lung carcinoma cell density on select polymer nanometer surface features for lung replacement therapies
Authors: Zhang Lijuan , chun Young Wook , Webster Thomas J 
Published: February 2010

AbstractPLGA (poly-lactic-co-glycolic acid) has been widely used as a biomaterial in regenerative medicine due to its biocompatibility and biodegradability properties. Previous studies have shown that cells (such as bladder smooth muscle cells, chondrocytes, osteoblasts, and vascular smooth muscle cells) respond differently to nano-structured PLGA surfaces (such as those with surface features less than 100 nm in at least one dimension) compared to nano-smooth surfaces. The purpose of the present in vitro research was to prepare PLGA films with various nanometer surface features and determine, for the first time, whether lung cancer epithelial cells respond differently to such topographies. Poly(dimethylsiloxane) (PDMS) molds prepared by placing PDMS onto various polystyrene monolayers and two solution evaporation methods were used to create nanometer surface features on PLGA. The intended spherical surface nano-topographies on PLGA with RMS values of 2.23, 5.03, 5.42 and 36.90 nm were formed, while PLGA surfaces with RMS values of 0.62 and 2.23 nm were obtained by different solution evaporation methods. Most importantly, lung cancer epithelial cells adhered less on the PLGA surfaces with an RMS value of 0.62, 2.23 and 5.42 nm after 4 hours of culture compared to any other PLGA surface created here. After three days, PLGA surfaces with an RMS value of 0.62 nm had much lower cell density than any other sample. In this manner, PLGA with specific nanometer surface features may inhibit lung cancer cell density which may provide for an important biomaterial for the treatment of lung cancer for a wide range of applications (from drug delivery to regenerative medicine).
Observation of Uptake and Distribution of Quantum Dots in Plants
Authors: Wang Annie R. , Xu Hengyi , Dixon John , Aguilar Zoraida Pascual 
Published: February 2010

AbstractEngineered nanoparticles that offer unique physical and chemical properties are rapidly flooding the market for commercial applications. The applications include, but are not limited to, cosmetic products, light emitting diodes, solid state display, drug delivery, disease diagnosis, nanoscale drug reformulations, MRI contrast agents, and new treatments. Predictions have indicated a dramatic increase in the market for nanotechnology and corresponding products to reach $1 trillion in 2012.
As a result of the predicted increase in the use of NPs as components of consumer product, the presence of engineered nanoparticles in the environment has sparked human health safety concerns. NPs may be introduced to organisms by inhalation, intravenous (usually purposefully), ingestion, or absorption through the skin. It is projected that the total production of NPs will reach 58,000 tons/year in 2011-2020 which assures human exposure to NPs at the workplace, in food and drinking water, and wearable consumer products. This paper addresses the QD distribution when plants are exposed to NPs. Mung beans were incubated with aqueous solutions of quantum dots and allowed to grow for 21 days. The seedlings were sectioned and observed under the microscope to establish the locations of NPs with respect to the roots, stem, and leaves.
Drug Deliverable, Self-assembled Rosette Nanotubes (RNTs) for Orthopedic Applications
Authors: Chen Yupeng , Song Shang , Fenniri Hicham , Webster Thomas J 
Published: February 2010

AbstractRosette nanotubes (RNTs) are novel, biomimetic, synthetic, self-assembled drug delivery agents. Because of base stacking and hydrophobic interactions, the RNT hollow-tube structure can be used for incorporating drugs. Another advantage of using RNTs is their ability to be injected and become solid at body temperatures for orthopedic applications without the use of any external stimuli (such as UV light or crosslinking agents). The nano-features of RNTs create a favorable, biologically-inspired, cellular environment. In this study, methods to incorporate dexamethasone (DEX, a bone growth promoting drug) into RNTs were investigated. The drug-loaded RNTs were characterized using Nuclear Magnetic Resonance (NMR), Diffusion Ordered Spectroscopy (DOSY) and Ultraviolet-visible Spectroscopy (UV-vis). Results showed that small molecular drugs with hydrophobic aromatic rings were incorporated into RNTs. Subsequent drug release experiments demonstrated that DEX was released from the RNTs and had a positive impact on osteoblast functions. Importantly, compared to other drug carriers, RNTs increased the total drug loading and was the highest when DEX was incorporated during the RNT self-assembly process. Thus, this study offered a novel drug delivery device that itself is bioactive and can be used to deliver a variety of drugs for various orthopedic applications.