bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Responsive Properties of Dibenzoylmethane Metallobiomaterials
Authors: Fraser Cassandra L. , Chen Jianbin , Pfister Anne , Zhang Guoqing , Chen Yin Jie 
Published: April 2011

ABSTRACTIncorporation of ligands and metals into polymers by controlled methods yields multifunctional responsive materials. Dibenzoylmethane (dbm) is a beta-diketone ligand that binds metal and metalloid ions such as boron, iron or europium in a bidentate fashion producing complexes with one or more dbm chelates. Modification of dbm with biocompatible poly(lactic acid) (PLA) allows materials processing and leads to responsive metallobiomaterials. This is accomplished by modification of dbm with hydroxyl groups (e.g. dbmOH), that serve as initiators for lactide polymerization. Improved control is noted when dbm is protected as iron or boron complexes, namely Fe(dbmOH)3 or BF2(dbmOH). Furthermore, the iron center in iron tris(dbmOH) also functions as a catalyst for the polymerization; no tin catalyst is required. Redorange iron-centered three arm star polymers, Fe tris(dbmPLA), are obtained. Acid sensitivity of these materials provides a method for dbm ligand dissociation, demetalation and production of dbmPLA macroligands for coordination to other metals such as Eu. Currently, dbmPLA and its polymeric iron complexes are being fabricated as nanoparticles. Light emitting B and Eu dbm complexes are also under investigation. Progress in the synthesis, characterization and nanoscale fabrication of dbm ligand and metal based polymeric biomaterials is reported.
Angle Resolved Thermal Desorption Studies for Poly(methylvinylidene cyanide) and Poly(vinylidenefluoride trifluoroethylene)
Authors: Ilie Carolina C. , Jacobson P. A. , Poulsen Matt , Rosa Luis G. , Sahadeva-Reddy D. , Takacs James M. , Ducharme Stephen , Dowben P. A. 
Published: April 2011

ABSTRACTWe compare water adsorption and desorption on ferroelectric copolymer poly(vinylidene fluoride-trifluoroethylene), and the dipole ordered polymer poly(methylvinylidene cyanide). The angle-resolved thermal desorption spectra prove that the absorbed water species interacts more strongly with poly(vinylidene fluoride-trifluoroethylene) than with poly(methylvinylidene cyanide). The angle resolved thermal desorption spectra shows large deviations from the cosine distribution for light illuminated poly(vinylidene fluoride-trifluoroethylene). Water desorption from poly(methylvinylidene cyanide) deviates from the cosine distribution without illumination.
Novel Silicon-Elastomers for Advanced Soft Lithography
Authors: Choi Kyung 
Published: April 2011

ABSTRACTHigh resolution pattern transfers in the nano-scale regime have been considerable challenges in ‘soft lithography’ to achieve nanodevices with enhanced performances. In this technology, the resolution of pattern integrations is significantly rely on the materials' properties of polydimethylsiloxane (PDMS) stamps. Since commercial PDMS stamps have shown limitations in nano-scale resolution soft lithography due to their low physical toughness and high thermal expansion coefficients, we developed stiffer, photocured PDMS silicon elastomers designed, specifically for nano-sized soft lithography and photopatternable nanofabrications.
Characterization of Electrospinning Fiber Diameter Distributions and Process Dynamics for Development of Real-Time Control
Authors: Yan Xuri , Gevelber Michael , Yu Jian , Rutledge Gregory 
Published: April 2011

ABSTRACTAn integrated data acquisition/actuator control system is developed to conduct experiments investigating the fundamental dynamics for different operating conditions in an electrospinning system. The relation between measured variables (fiber current, whipping angle, jet length, and expulsion cone volume) to the resulting fiber diameter distribution is analyzed.
Fabrication of Energy Storage Media BST/PVDF-PAn
Authors: Luo Dabing , Guo Yan , Hao Hua , Liu Hanxing , Ouyang Shixi 
Published: April 2011

ABSTRACTPermittivity and anti-voltage ability commonly determined the energy storage density of material. Although composite could be molded easier than ceramic, its lower energy storage density prevented the material from application since the polymer usually took on poor dielectric constant. In order to enhance the energy storage performance of composite, PAn was introduced to PVDF by emulsion polymerization. SEM of the co-polymers showed that they could construct continuous media till the concentrate of aniline reached 25% while polymerizing. The permittivity of polymer rose along with the concentrate increasing of aniline and pH falling value of retreating solution. The permittivity and anti-voltage strength of composite also charged correspondingly. As a consequence, the energy storage density innovated much higher than ever. The maximum energy storage density could approach 0.9185Johr/cc.
Nano-Structural Control of Molecular-Pore Stacked (MPS) SiOCH Films Using Plasma Copolymerization Reaction
Authors: Yamamoto Hironori , Ito Fuminori , Tada Munehiro , Takeuchi Tsuneo , Furutake Naoya , Hayashi Yoshihiro 
Published: April 2011

ABSTRACTA novel plasma co-polymerization technology, using flexibly-mixed molecular gas of 6-membered ring-type vinyl-siloxane and 8-member ring-type one, has been developed for new interlayer dielectric film.
DNA Hybridization Detection using Fluorescent Zinc Selenide Quantum Dots
Authors: Wang Jun , Lei Pedro , Andreadis Stelios , Heckler Tracy , Mei Bing , Qiu Qi , Mountziaris T J 
Published: April 2011

ABSTRACTThis work focuses on the development of biological analysis tools using zinc selenide quantum dots (ZnSe QDs). Conjugating water-dispersible ZnSe QDs with oligonucleotides of increasing length was found to increase their photoluminescence (PL) intensity monotonically up to a certain length. Varying the sequence of the oligonucleotide without changing its length does not produce any measurable PL intensity change. The stability of QDs in water was significantly enhanced after conjugation with oligonucleotides. DNA hybridization was studied using QDs functionalized with complementary oligonucleotides. Hybridization of complementary QD-oligonucleotide complexes causes significant PL intensity amplification and a measurable red shift of the PL emission peak. The QD-oligo complexes are very stable in water under ambient dark conditions. Finally, a size-dependent optimal dilution of free QDs was discovered, corresponding to an optimal inter-QD-spacing that results in the highest PL emission intensity from as-prepared QD dispersions. Ongoing experiments in our laboratory aim to develop multiplexed DNA probes and immunoassays by employing luminescent QDs emitting at different wavelengths.
Microfabricated, Wireless, Magnetoelastic Micro-Particles for the Detection of Bacillus Anthracis Spores
Authors: Wan Jiehui , Johnson Michael L. , Shu Huihua , Petrenko Valery A. , Chin Bryan A. 
Published: April 2011

ABSTRACTMagnetoelastic resonance biosensors were fabricated by immobilizing a bio-molecular recognition element onto the surface of Fe79B21 magnetoelastic particles (MEP). These sensors can be measured wirelessly and remotely for both in-air and in-liquid bacteria detection. Filamentous bacterio-phage that was selected specifically for the detection of Bacillus anthracis spores was employed as the biomolecular recognition element and immobilized onto the MEPs' surfaces. Attachment of the spores to the sensor surface due to specific phage-spore binding results in a shift in the resonance frequency of the biosensor. Insitu measurement of the resonance frequency of biosensors of 5×100×500 microns were used to determine the sensor response as a function of spore concentrations of 103 to 108 cfu/ml. Specificity of the sensor was evaluated by conducting tests using a mixture of Bacillus anthracis Sterne strain, Bacillus cereus and Bacillus megaterium spores.
Connected Electrodes by the Growth of Germanium Dioxide Nanowires
Authors: Wu Chun-I , Hogan Tim P. 
Published: April 2011

ABSTRACTGermanium dioxide nanowires have gained significant interest lately due to the the bandgap of 2.44 eV, and high index of refraction, n=1.63. In this paper we aim at investigating the lateral growth of high density metal-catalyzed germanium dioxide nanowires between electrodes. The gaps between two electrodes varied. The catalyst metal was placed on the electrodes, followed by a thermal annealing process, resulting in lateral growth of germanium dioxide whiskers with several microns length and eventually the formation of bridge-like nanostructures. These whiskers have certain unique properties, such as a high surface-to-volume ratio and the capability of connecting two electrodes. Because of these properties, the growth of whiskers from the electrodes has the potential to be developed as electronic devices such as nanosensors. These products are characterized by scanning electron microscopy (SEM), as well as X-Ray diffraction (XRD).
Protein Assembly Through Site-specific Interactions with Gold Nanoparticles
Authors: Hu Minghui , Qian Luping , Briñas Raymond P , Lymar Elena S , Hainfeld James F 
Published: April 2011

ABSTRACTA universal method is described to design and construct protein-nanoparticle assemblies controlled by nanoparticle functionality, and placement of genetic tag into proteins. Well-defined binding complexes of nanoparticles and two proteins, the adenovirus serotype 12 knob and the mycobacterium tuberculosis 20S proteasome, were formed through site-specific binding between 6x-histidine tags in proteins and nickel-nitrilotriacetic acid functional groups on gold nanoparticles.
Surface Stress Generation During Formation of Alkanethiol Self-assembled Monolayer (SAM)
Authors: Kanaga Subramanian Kanaga Karuppiah , Zhang Ruqin , Shrotriya Pranav , Chandra Abhijit , Sundararajan Sriram 
Published: April 2011

ABSTRACTMicro-machined cantilevers coated with self-assembled monolayers (SAM) of alkanethiols are being utilized as sensing elements for new generation of high-sensitivity chemical and biological sensors. Presence of chemical species is detected by resolving the surface stress change associated with absorption/adsorption of analyte molecules on the sensitized cantilever. Challenges to widespread use of micromechanical cantilever sensors are: susceptibility to vibrations, integration in a single device and understanding the mechanism governing surface stress generation. In the current work, surface stress development associated with formation of self-assembled-monolayers of alkanethiols was characterized using curvature interferometry. In order to understand the molecular mechanism underlying the surface stress generation, a multi-scale model is developed to predict the surface stress generated during absorption of the alkanethiols on a gold film.
Use of Anodized Titanium in Drug Delivery Applications
Authors: Yao Chang , Balasundaram Ganesan , Webster Thomas 
Published: April 2011

ABSTRACTOne approach to improve the performance of current titanium implants is to create nanostructures via surface modification. Anodization is known to produce nanotubular structures on titanium surfaces when using fluorine containing solutions. Previous studies revealed enhanced osteoblast (bone-forming cell) adhesion and calcium deposition on anodized titanium possessing nanotubular structures compared to unanodized titanium. Moreover, it was found that protein adsorption (specifically, vitronectin and fibronectin) prior to cell adhesion increased on anodized compared to unanodized samples. These results all indicate that anodized titanium would be a good candidate for novel orthopedic implants. The nanotubes created by anodization have an inner diameter from 40 to 100 nm and a depth of a few hundred nanometers. In the present study, the drug delivery capability of such nanotubular structures was further characterized. Three different model drugs were tested: immunoglobulin G for foreign body response, bone morphogenetic protein active fragment for new bone growth, and penicillin/streptomycin for antimicrobial. First, these proteins were allowed to adsorb onto substrates for 24 h under room temperature. Then, the substrates with absorbed proteins were rinsed and transferred to new buffer solution kept at 37 °C. Buffer solution was collected and changed everyday. Finally, protein release from each substrate was measured using a commercial BCA assay kit. Results showed decreased immunoglobulin G adsorption, increased bone morphogenetic protein and penicillin/streptomycin adsorption on anodized titanium compared to unanodized ones. The release behavior of each protein on anodized and unanodized titanium is also studied.
Advanced Organic-inorganic Hybrid Coatings Having Both High Gas Barrier Properties and Abrasion Resistance
Authors: Nishiura Katsunori , Takaki Toshihiko , Nakaura Makoto 
Published: April 2011

ABSTRACTIt is important to develop flexible transparent polymer films having high gas barrier properties and abrasion resistance because new applications involving transparent polymer films for flat panel displays require these properties. We report on organic-inorganic hybrid coatings of polyvinylalcohol (PVA)/polyacrylicacid (PAA)-silica, which have high gas barrier properties almost equivalent to those achieved by the dry coating process. The hybrid coatings were prepared by the sol-gel reaction of alkoxysilane in a PVA/PAA aqueous solution. In order to obtain transparent coating films, 3-aminopropyltrimethoxysilane (APTMOS) was used as a compatibilizer in the sol-gel reaction of tetramethoxysilane (TMOS). No structure could be seen in the TEM of the cross-sectional coating layer, indicating that polymers and silica were mixed homogeneously. PVA/PAA-silica hybrid coatings were shown to have excellent abrasion resistance based on the ΔHaze index. O2 permeability of PVA/PAA-silica hybrid coatings evaluated by MOCON under the conditions of 23°C, 90% RH was lower than that of PVA/PAA polymer coating, which suggests that silica affects the barrier property of the hybrid coating in humid conditions. Furthermore, O2 permeability decreased as silica content increased in the coatings. Unexpectedly, high gas barrier properties appeared when the silica content exceeded 50 wt%. From the result of element distribution analysis measured by EF-TEM, it was confirmed that phase separation occurred between PVA/PAA and silica on a nanometer scale and silica forms continuous structures, which are considered to suppress O2 permeability.
Thermal and Pressure Sensing by Chemoreceptive Neuron MOS Transistors (CνMOS) with PVDF Coating
Authors: Jacquot Blake , Muñoz Nini , Kan Edwin C. 
Published: April 2011

ABSTRACTThis paper reports the integration of poled 10μm +/- 1μm P(VDF-TrFe) copolymer thin films with an adapted non-volatile, foundry-compatible CMOS structure (CνMOS) for the potential purposes of in-vivo piezoelectric and pyroelectric sensing. This structure allows for direct, reliable interaction between the sensing transducer and the highly sensitive MOSET gate stack without the need for an external reference electrode or chopper, as other designs may require.
Interactions Between Carbon Nanotubes and Bacteria
Authors: Raja Pavan M. V. , Ajayan Pulickel M. , Nalamasu Omkaram , Sharma Anurag 
Published: April 2011

ABSTRACTWhile carbon nanotubes (CNTs) possess diverse application potential ranging from polymer nanocomposites to nanostructured therapeutic devices, their environmental implications are still not well understood. In this study, we conducted experiments to monitor changes in bacterial physiology as a consequence of interactions with the CNTs. Our experiments included a common anaerobe,Escherichia coli, in an SWNT system as a model for understanding the environmental implications of CNTs. Observations over several weeks indicated that the bacteria in the presence of SWNTs showed significant morphological changes, that included elongation. It is interesting to note that similar morphological changes have been reported in response to extreme temperature and pressure, chemical agents, and quantum dots. In this presentation, the authors will present further physiological evidence, such as bacterial growth and substrate consumption rates, towards defining a possible bacteria-CNT interaction model consistent with these experimental observations, and will discuss the overall environmental implications.
Bulk AlN Crystal Growth on SiC Seeds and Defects Study
Authors: Lu Peng , Edgar J H , Cao C , Hohn K , Dalmau R , Schlesser R , Sitar Z 
Published: April 2011

ABSTRACTSublimation growth of AlN was performed on Si-face, 8 ° off-axis 4H-SiC (0001) and 3.5 ° off-axis 6H-SiC (0001) seeds. AlN layers 500 - 900 μm thick and 20 mm in diameter were grown at 1830 °C by consecutive growths and continuous growth. The c-axis growth rate was approximately 8 - 18 μm/hr. On both the 8 ° and 3.5° off-axis SiC substrates, “step” features formed on the AlN surface with uniform terrace width and step density. The step heights and terrace widths increased as the AlN grew thicker. In addition, a single facet of 9 mm × 5 mm formed on the top of the layer grown on the 3.5 ° off-axis SiC. High resolution x-ray diffraction showed the AlN (00.2) 2θ value shifted from pure AlN toward SiC. Approximately 3 – 4 at% of SiC was detected at the surface of the AlN by XPS. Molten KOH/NaOH etching revealed that both samples had Al-polar surface with dislocation densities on the order of 106-107 cm−2. The cross-section etching showed the re-nucleation layer and void defects at the interfaces of the consecutive growths.
Growth and Polarity Control of GaN and AlN on Carbon-face SiC by Metalorganic Vapor Phase Epitaxy
Authors: Fu Yi , Ni Xianfeng , Xie Jingqiao , Biyikli N , Fan Qian , Chevtchenko S , Özgür Ü , Morkoç Hadis , Ke You , Devaty Robert , Choyke W. J. , Inoki C. K. , Kuan T. S. 
Published: April 2011

ABSTRACTGrowth and polarity control of GaN and AlN on carbon-face SiC (C-SiC) by metalorganic vapor phase epitaxy (MOVPE) are reported. The polarities of GaN and AlN layers were found to be strongly dependent on the pre-growth treatment of C-SiC substrates. A pre-flow of trimethyaluminum (TMAl) or a very low NH3/TMAl ratio results in Al(Ga)-polarity layers on C-SiC. Otherwise, N-polarity layers resulted. The polarities of AlN and GaN layers were conveniently determined by their etching rate in KOH or H3PO4, a method reported earlier. We suggest that the Al adatoms, which have a high sticking coefficient on SiC, form several Al adlayers on C-SiC and change the incorporation sequence of Ga(Al) and N leading to metal polarity surface. In addition, the hexagonal pyramids, typical on N-polarity GaN surface, are absent on N-polarity GaN on off-axis C-SiC owing to high density of terraces on off-axis C-SiC. The properties of GaN layers grown on C-SiC are studied by X-ray diffraction.
Mg-doped N-polar InN Grown by RF-MBE
Authors: Muto Daisuke , Naoi Hiroyuki , Takado Shinya , Na Hyunseok , Araki Tsutomu , Nanishi Yasushi 
Published: April 2011

ABSTRACTWe have investigated the growth properties of Mg-doped N-polar InN films grown by radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE). We found that the Mg-doped InN films had smaller grain size than non-doped films, and furthermore the grain size decreased with an increase in Mg doping amount. Non-doped InN exhibited a single X-ray diffraction (XRD) peak of (0002) h-InN. On the other hand, the Mg-doped InN produced a weak XRD peak of (111) c-InN in addition to a strong peak of (0002) h-InN. These results indicate that the Mg doping decreased the surface migration length of In atoms. From Hall-effect measurements, all the samples were shown to have n-type conductivity. Mg-doped InN grown with Mg cell temperatures of 130 and 135°C had carrier concentrations that were about half (i.e., ∼4.5×1018 cm−3) that of the non-doped InN. However, the carrier concentration tended to increase with further supply of Mg. These results indicate that Mg-doping causes a trade-off between a carrier decreasing effect from the Mg acceptors and a carrier increasing effect from defects caused by the poor surface migration of In atoms.
Experimental Analysis of the Spontaneous Polarization Field in GaN by UHV-cathodoluminescence
Authors: Finke Martina , Fuhrmann Daniel , Rossow Uwe , Hangleiter Andreas 
Published: April 2011

ABSTRACTCathodoluminescence spectra of GaInN quantum well structures show a strong change of intensity and a emission energy shift during electron beam irradiation. Measurements on samples with quantum well positions varying in depth show, that the spontaneous field, witch is usually screened by surface charges, penetrates the sample in a timescale of minutes and reduces the quantum confined Stark effect.
Erbium-doped GaN epilayers synthesized by metal-organic chemical vapor deposition
Authors: Ugolini C. , Nepal N. , Lin J. Y. , Jiang H. X. , Zavada J. M. 
Published: April 2011

ABSTRACTGaN is an excellent host for Er due to the low thermal quenching of radiative intra-4f Er3+ transitions at 1.54 μm. Er doped GaN structures are promising for emitters and amplifiers operating at the main telecommunication wavelength. In recent studies, Er doped III-Nitride epilayers were obtained by ion implantation, hydride vapor phase epitaxy (HVPE), metal organic molecular beam epitaxy (MOMBE), or molecular beam epitaxy (MBE). But, in-situ Er doping of III-nitride epilayers has not been achieved by metal organic chemical vapor deposition (MOCVD), mostly due to the low vapor pressure and lack of suitable, metal organic Er sources. Since n and p type III-nitride epilayers with excellent electrical properties and high crystalline quality are easily achieved by the MOCVD method, in-situ incorporation of Er into III-nitride materials by MOCVD is a very attractive method for creating highly efficient optoelectronic devices operating at 1.54 μm. We report on the experimental study and synthesis of Er doped GaN by MOCVD. Photoluminescence (PL) with above and below bandgap excitation energies were employed to study the optical properties of Er doped GaN. PL spectra of these Er doped layers exhibit a strong 1.54 μm emission, corresponding to the intra-4f transition of the 4I13/2 (first excited state) to the 4I15.2 (ground state) of Er3+. The mechanisms of optical transitions involving different excitation energies, and potential applications of Er doped GaN structures in the communication wavelength are also discussed.
Preparation of High Conductive Cubic Boron Nitride Thin Films by in-situ zinc Doping
Authors: Nose Kenji , Yoshida Toyonobu 
Published: April 2011

ABSTRACTSilicon and zinc were doped to cubic boron nitride (cBN) thin films by sputtering bulk dopant sources during the film deposition. Concentrations of these two elements showed different in-plane distributions, presumably caused by the difference of the sticking probability on the growing surface. Silicon impurity did not behave as an active dopant in cBN. However, zinc doping enhanced the electric conductivity from 10−8 to 10−2 (Ω−1cm−1) as the zinc concentration increased from undoped to approximately 2 %.
The Influence of Device Structure on High-electric-field Effects and Reliability of AlGaN/GaN HFETs
Authors: Kuang Weiwei , Trew Robert J , Bilbro Griff L , Liu Yueying 
Published: April 2011

ABSTRACTAlGaN/GaN HFETs have demonstrated excellent RF performance, but the devices still suffer from a reliability problem. The decrease of the dc current and RF output power over time is attributed to gate tunneling which is determined by the magnitude of electric field at the gate edge. In this work, in order to improve the reliability of AlGaN/GaN HFETs, a 2D drift-diffusion tool is used to explore the relationship between the magnitude of electric field and different device structures through modifications of the 2DEG sheet charge density, AlGaN barrier layer thickness, AlGaN doping concentration and gate to drain spacing. The effect of field plates is also investigated. It was found that decreasing 2DEG sheet charge density results in much improved reliability, although the current and output power are somewhat reduced.