bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ionic conductivity in nanocrystalline Gd doped ceria
Authors: Baldinozzi Gianguido , Simeone David , Gosset Dominique , Dollé Mickael , Petot-Ervas Georgette 
Published: August 2010

AbstractWe have synthesized Gd-doped ceria polycrystalline samples (5, 10, 15 %mol), having relative densities exceeding 95% and grain sizes between 30 and 160 nm after axial hot pressing (750 °C, 250 MPa). The samples were prepared by sintering nanopowders obtained by sol-gel chemistry methods having a very narrow size distribution centered at about 16 nm. SEM and X-ray diffraction were performed to characterize the sample microstructures and to assess their structures. We report ionic conductivity measurements using impedance spectroscopy. It is important to investigate the properties of these systems with sub-micrometric grains and as a function of their composition. Therefore, samples having micrometric and nanometric grain sizes (and different Gd content) were studied. Evidence of Gd segregation near the grain boundaries is given and the impact on the ionic conductivity, as a function of the grain size and Gd composition, is discussed and compared to microcrystalline samples.
Transport in Polyiodide Networks of a Self-Assembled Lithium Iodide Battery
Authors: Yourey William M. , Weinstein Lawrence , Amatucci Glenn G. 
Published: August 2010

AbstractAs MEMS devices for biomedical and other applications continue to develop and decrease in dimensions, the demand for power supplies with the appropriate size and energy density continues to grow. Although energy density is an important factor, one of the most crucial factors is the ability to fabricate cells in a variety of shapes so to enable the greatest design flexibility when fabricating a device. Recently our group has introduced an electrochemically self formed battery to grant a path towards the greatest flexibility. In short, a nanocomposite of an alkali halide such as lithium iodide is placed between current collectors and polarized thereby creating a lithium anode and polyiodide cathode in-situ. As with primary lithium-iodine cells the transport within the cathode is a complex mechanism involving the Li+, I-, and e- all within the polyiodide network. After our recent work on in-situ EIS evaluation of the technology, we have launched on an effort to greater understand the limiting transport mechanisms in the positive electrode as a function of polyiodide network development.
An in-depth characterization study was performed on the LiI-I2-PVP-H20 at various molar ratios to understand the structural and conductivity changes that take place during formation of the cell A combination of AC impedance and DC polarization studies were used for the impedance characterization in conjunction with blocking electrode methodology for separating the conductivity into its electronic and ionic portions. Also, FTIR and Raman were used to structurally characterize the samples for both the polyiodide formation and the interaction between the polyiodides and polyvinylpyrrolidone (PVP). Being non conjugated, PVP was chosen as it does not intrinsically contribute to the conductivity of the composite but does induce the formation of polyiodide species. As different molar ratio composites are prepared, the concentration of different polyiodide species (I3-, I5-, In-) within the composite change and affect the overall conductivity. A 3-dimensional plot of composite conductivity reveals a high electronic conductivity ridge for samples containing either LiI anhydrous or monohydrate at a constant I2 to PVP ratio. These 3-dimensional plots also allow us to correlate represent in an ex-situ format the electronic and ionic conductivity of the cathode/electrolyte at various depths of discharge.
Diffusion Paths for the Formation of Half-Heusler Type Thermoelectric Compound TiNiSn
Authors: Asami Chihiro , Kimura Yoshisato , Kita Takuji , Mishima Yoshinao 
Published: August 2010

AbstractHalf-Heusler compound TiNiSn is one of the most promising candidates of thermoelectric materials which can be used to directly convert the waste heat to clean electric energy at high temperatures (around 1000 K). Thermoelectric power generation is an appealing approach for conserving energy and preserving the global environment. Half-Heusler compounds have the cubic C1b type ordered structure and show semiconducting behavior when their valence electron count (VEC) is around 18. TiNiSn is the most attractive one not only because it has excellent thermoelectric properties but also it consists of eco-friendly elements which are neither toxic nor costly. However, TiNiSn has a bothersome problem that fabrication of single phase TiNiSn alloy is quite difficult. We have found that TiNiSn phase forms by the ternary peritectic reaction. Thereby, inevitable non-equilibrium solidification results in the formation of impurity coexisting phases which tend to decrease thermoelectric properties.
In the present work, to establish the basis of new fabrication processes for TiNiSn alloys, we have started from the investigation on the diffusion paths which are closely related to the formation of TiNiSn phase. The diffusion behavior was evaluated using solid/liquid diffusion couples composed of the binary Ti-Ni intermetallic compounds and Sn liquid phase, where we have selected TiNi, TiNi3 and Ti2Ni as solid phases for instance. The most interesting result is that the single-phase TiNiSn phase layer forms at the TiNi/Sn(L) interface during annealing at 1073 K for only 1 h. Moreover, faceted grains of TiNiSn single-crystal grow at the interface toward the liquid Sn phase. We have confirmed two interesting microstructural features using EBSD analyses. One is that most of these TiNiSn single-crystals have the same crystallographic orientation, and the other is that TiNiSn phase layer formed on the TiNi side of the interface consists of very fine sub-microns grains. While TiNiSn solely forms at the TiNi interface, Heusler TiNi2Sn also forms with TiNiSn at the TiNi3 interface and Ti6Sn5 tends to coexist at the Ti2Ni interface.
Phase Stability of the L12 Compound and Microstructural Changes in Co-(W or Mo)-Ta Ternary Alloys
Authors: Chinen Hibiki , Omori Toshihiro , Oikawa Katsunari , Ohnuma Ikuo , Kainuma Ryosuke , Ishida Kiyohito 
Published: August 2010

AbstractMicrostructural investigations of Co-5W-2.5Ta (at.%) and Co-4Mo-4.5Ta (at.%) ternary alloys were conducted. Fine coherent precipitates were observed in these alloys annealed at 800°C, and the crystal structures of precipitates (γ’) and matrix (γ) phase were identified as the L12 and A1 structure, respectively, by transmission electron microscopy. Cellular precipitation with a γ+χ(D019) lamellar structure also proceeded at grain boundaries, and the alloys aged for a longer time only showed the γ+χ two-phase microstructure instead of the γ’ phase. With aging at around 800°C, the peak hardness of these alloys with a γ+γ’ two phase structure was about 580 Hv.
Deformation Behavior of Niobium Silicides during High Temperature Compression
Authors: Sekido Nobuaki , Miura Seiji , Yamabe-Mitarai Yoko , Kimura Yoshisato , Mishima Yoshinao 
Published: August 2010

AbstractDeformation behavior of (Nb)/α-Nb5Si3 two-phase alloys is examined by high temperature compression tests. The alloys exhibit brittle fracture behavior at temperatures up to 1473 K, while reasonable compressive deformability at 1673 K. Upon high temperature compression of the alloys, the flow stress gradually decreases after the peak stress due to the recrystallization/recovery in the (Nb) phase, as well as the increase in the density of mobile dislocations within the α-Nb5Si3 phase. Two types of slip systems that operate in α-Nb5Si3 have been identified as {011)<11-1] and {001)<100] in the present study.
Absorption-induced Deformations of Nanofiber Yarns and Nanofibrous Webs
Authors: Monaenkova Daria , Andrukh Taras , Kornev Kostya 
Published: August 2010

AbstractCurrent advances in manufacturing of nanotubular and nanofibrous materials with high surface- to - volume ratios call for the development of adequate characterization methods and predictive estimates of the materials absorption capacity. Extremely high flexibility of these materials poses a challenge: their pore structure easily changes upon contact with the fluid in question. One more complication is that the absorption process is sufficiently fast: one hundred micron droplets disappear in milliseconds. This paper sets a physical basis for analyses of absorption processes in nanotubular and nanofibrous materials. As an example, we study absorption of droplets by yarns made of nanofibers and nanofibrous webs. We show that absorption can induce different types of deformations: visible deformations of the yarn profile and deformations of the yarn diameter/length caused by the capillary forces. Using experimental data and theory, we estimate elastic and transport characteristics of the nanofibrous materials. The reported experiments and proposed theory open a new area of research on absorption-induced deformations of nanotubular and nanofibrous materials and show their potential applications as sensors to probe minute amount of absorbable liquids.
Investigation of the Crystalline Orientations and Substrates Dependence on Mechanical Properties of PZT Thin Films by Nanoindentation
Authors: Liu Dan , Yoon Sang H , Zhou Bo , Prorok Barton C , Kim Dong-Joo 
Published: August 2010

AbstractIn this paper, we investigated the effects of the substrates and crystalline orientations on the mechanical properties of Pb(Zr0.52Ti0.48)O3 thin films. The PZT thin films were deposited by sol-gel method on platinized silicon substrates with different types of layer materials such as silicon nitride and silicon oxide. The crystalline orientations of PZT thin films were controlled by combined parameters of a chelating agent and pyrolysis temperature. A nanoindentation CSM (continuous stiffness measurement) technique was employed to characterize the mechanical properties of those PZT thin films. It was observed that (001/100)-oriented films show a higher Young’s modulus compared to films with mixed orientations of (110) and (111), indicating a clear dependence on film orientation. The influence of substrates on the mechanical properties of PZT thin films was also characterized. Finally, no significant influence of the film thickness was found on the mechanical properties of films thicker than 200 nm.
Surface Stability and Electronic Structure of Hydrogen and Fluorine Terminated Diamond Surfaces: a First Principles Investigation
Authors: Sen Fatih Gurcag , Qi Yue , Alpas Ahmet T 
Published: August 2010

AbstractThe stability and electronic structure of fully H or F terminated and mixed H and F terminated diamond (111) surfaces were studied using first principles calculations. It was found that F atoms on the surface, like H, formed sp3 type bonding with C atoms, which resulted in a more stable 1×1 configuration rather than the π-bonded 2×1 construction of clean diamond. A phase diagram showing the stable surface composition regions was constructed as a function of chemical potentials of H and F. The diagram shows that the surface with 75% F (25% H) termination was unstable. The F terminated surface was more stable than H termination due to the formation of strong ionic C-F bonding and the close packing of the large F atoms. Due to the attractive forces developed between F atoms, a close packed surface was formed. Additionally, the exposure of C to the environment became restricted because of the large size of F atoms. Hence, F terminated diamond surface was more chemically inert compared to H terminated surface. To bring two F terminated surfaces together, a large repulsive force was required due to the negative charge on F atoms, and this led to low adhesion between two F terminated diamond surfaces compared to two H terminated surfaces.
Lithographically Fabricated 10-Micron Scale Autonomous Motors
Authors: Wang Yang , Fei Shih-to , Crespi Vincent H. , Sen Ayusman , Mallouk Thomas E. 
Published: August 2010

ABSTRACTSelf-propulsion and directed movement of nano- and micro-particles can in principle provide novel components for applications in microrobotics and MEMS. Our research involves the design of catalytic propulsion systems and the control of colloidal movement based on this principle. We have designed autonomous nanomotors that mimic biological motors by using catalytic reactions to generate forces derived from chemical gradients. Through architectural control of bimetallic catalytic particles, we have recently developed systems that undergo more complex movement. For example, we have constructed 10-micron scale rotary motors by contact lithography. In these chiral motors, bimetallic Au-Pt patterns are free-standing and move in the pattern predicted by theory. These studies demonstrate that by designing the proper architecture, one can tailor the pattern of movement to specific applications, such as changing from translational to rotational movement. The potential for elaboration of these designs to more complex micro-machine assemblies is discussed.
Percutaneous Biomedical Device with a Regenerative Materials Interface
Authors: Peramo Antonio , Marcelo Cynthia L. , Goldstein Steve , Martin David C. 
Published: August 2010

ABSTRACTWe have developed an in vitro culture system composed of organotypic human skin explants interfaced with titanium rods or stainless steel fixator pins. The use of this interface provides a model to evaluate strategies for creating a stable, long-term connection with living skin and chronic percutaneous devices. Our hypothesis is that the delivery of specific biomaterials at this interface will create a dynamic, slowly flowing matrix for skin biointegration, local administration of drugs or antimicrobials. We define this concept as the generation of an artificial mucosa, because it mimics the situation of several epithelial tissues (like the periodontal junction between the tooth and the junctional epithelium) where antimicrobial peptides and mucins are constantly extruded.
Study of Protein Adsorption onto a Polymer Film by in-situ UV Attenuated Total Reflectance Spectroscopy
Authors: Bratescu Maria-Antoaneta , Fujita Syohei , Saito Nagahiro , Takai Osamu 
Published: August 2010

AbstractOur work presents results on human plasma protein adsorption onto a polyacrylic acid (PAA) film prepared via surface wave plasma (SWP) induced graft polymerization. The PAA film prepared in this manner is characterized by a carboxyl functional group and a constant contact angle in water of 35°. The adsorption kinetics of human plasma fibrinogen (HPF) and human serum albumin (HSA) proteins were measured by in-situ UV-ATR spectroscopy. The free energy of adsorption on PAA treated as well as untreated surfaces was −28 kJ M−1 and −22 kJ M−1 for HPF and HSA, respectively, regardless of surface chemistry. We determined that 14 μM and 6 μM HPF concentrations are enough to cover half of the maximum possible of surface coverage on silica and PAA film, respectively. HSA protein concentrations of 154 μM and 118 μM are enough to cover half of the maximum accessible surface of silica and PAA film, respectively. For surface treatment of implants with PAA polymer and protein, the necessary protein concentration for effective surface coverage should be known.
Advanced Functional Graphite-Coated Magnetic Nanoparticles as RF Thermal Ablation Agents for Cancer Therapies
Authors: Xu Yang , Mahmood Meena Waleed , Li Zhongrui , Dervishi Enkeleda , Trigwell Steve , Zharov Vladimir P. , Ali Nawab , Saini Viney , Biris Alexandru R. , Lupu Dan , Biris Alexandru S. 
Published: August 2010

AbstractGraphitic shells coated ferromagnetic cobalt nanoparticles (C-Co-NPs) with diameters of around 7-9 nm cubic crystalline structures were synthesized by catalytic chemical vapor deposition (CCVD). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis indicated that the Co-NPs inside the carbon shells were preserved in the metallic state. Confocal microscope images revealed effective penetrations of C-Co-NPs through plasmatic membranes into the nucleus of the cultured HeLa cancerous cells. Low RF radiation of 350 kHz triggered the cell death, process that was found to be dependent on the NPs concentration and application time. Compared to carbon nanostructures such as single wall carbon nanotubes, super paramagnetic cobalt nanoparticles demonstrated higher specificity for RF absorption and heating. This work indicates a great potential of a new technology for tumor thermal ablation.
In vivoMonitoring of Gold Nanorods and Tissue Damage Mediated with Their Photothermal Effect
Authors: Niidome Takuro , Akiyama Yasuyuki , Shimoda Kohei , Kawano Takahito , Mori Takeshi , Katayama Yoshiki , Niidome Yasuro 
Published: August 2010

AbstractGold nanorods have a strong surface plasmon band at the near infrared region. The absorbed light energy is then converted to heat. Since near infrared light can penetrate deeply into tissue, gold nanorods are expected to be used as a contrast agent for bioimaging using the near infrared light and photosensitizers for photothermal therapy. The surface plasmon bands of intravenously injected the gold nanorods were directly monitored from the mouse abdomen by using a spectrophotometer equipped with an integrating sphere. The absorbance at 900 nm from PEG5,000-modified gold nanorods immediately increased after injection and reached a plateau. The injection of phosphatidylcholine-modified gold nanorods also increased the absorbance at 900 nm, but the absorbance decreased single exponentially with a 1.3-min half-life. To demonstrate photothermal tumor therapy, the PEG-modified gold nanorods were directly injected into subcutaneous tumors in mice, then, near infrared laser light was irradiated to the tumor. After the treatment, significant suppression of tumor growth was observed.
A Self-assembled, Drug-deliverable Nanomaterial for Cartilage Tissue Engineering
Authors: Chen Yupeng , Fenniri Hicham , Webster Thomas J. 
Published: August 2010

AbstractThe current clinical treatment of cartilage defects involves autologous chondrocyte implantation into cartilage defect sites. However, one of the complications associated with this method is the lack of bonding between the implanted materials and natural tissue. Helical rosette nanotubes (HRNs) are novel biomimetic self-assembled supramolecular structures whose basic building blocks are DNA base-pairs. HRNs are similar in size to collagen in cartilage. Moreover, previous studies have shown that HRNs are biocompatible and increase the adhesion of numerous cells compared to other commonly used cartilage implant materials (like hydrogels and Ti). In addition, HRNs can solidify into a viscous gel at body temperatures under short periods of time. Thus, it is hoped that HRNs can serve as a novel in situ tissue implant to improve cartilage cell adhesion and functions. In this study, in order to heal cartilage rupture and regenerate cartilage during possible implantation, the mechanical properties of select hydrogel/HRN composites were tested. In addition, electro-spinning was used to generate three-dimensional, implantable, composite fibers encapsulated with chondrocytes and fibroblast-like type-B synoviocytes (SFB cells, a type of mesenchymal stem cell). Importantly, results showed that drug-delivered HRNs enhanced hydrogel adhesive strength and created a scaffold with nanometer-rough surface structures pertinent for cartilage regeneration. In this manner, this study provided an alternative cartilage regenerative material which relies on nanotechnology that can be injected as a liquid, solidify at body temperatures under short periods of time, have suitable mechanical properties to collagen, and promote cell functions.
Decomposition of Mixed Phase Silicon Raman Spectra
Authors: Ledinský Martin , Stuchlík Jiri , Vetushka Aliaksei , Fejfar Antonin , Kočka Jan 
Published: August 2010

AbstractSeries of Raman spectra were measured for microcrystalline silicon thin film with variable crystallinity. Five sets of Raman spectra (corresponding to excitations at 325 nm, 442 nm, 514.5 nm, 632.8 nm and 785 nm wavelengths) were subjected to factor analysis which showed that each set of spectra consisted of just two independent spectral components. Decomposition of the measured Raman spectra into the amorphous and the microcrystalline components is illustrated for 514.5 nm and 632.8 nm excitations. Effect of the light scattering on absolute intensity of Raman spectra was identified even for excitation wavelength highly absorbed in the mixed phase silicon layers.
High Efficiency Large Area a-Si:H and a-SiGe:H Multi-junction Solar Cells Using MVHF at High Deposition Rate
Authors: Xu Xixiang , Beglau Dave , Ehlert Scott , Li Yang , Su Tining , Yue Guozhen , Yan Baojie , Lord Ken , Banerjee Arindam , Yang Jeff , Guha Subhendu , Hugger Peter G. , Cohen David J. 
Published: August 2010

AbstractWe have developed high efficiency large area a-Si:H and a-SiGe:H multi-junction solar cells using a Modified Very High Frequency (MVHF) glow discharge process. We conducted a comparative study for different cell structures, and compared the initial and stable performance and light-induced degradation of solar cells made using MVHF and RF techniques. Besides high efficiency, the MVHF cells also demonstrate superior light stability, showing <10% degradation after 1000 hour of one-sun light soaking at 50 °C. We also studied light-induced defect level and hydrogen evolution characteristics of MVHF deposited a-SiGe:H films and compared them with the RF deposited films.
Study of Solid/liquid Interfaces in Organic Field-effect Transistors with Ionic Liquids
Authors: Ono Shimpei , Miwa Kazumoto , Seki Shiro , Takeya Jun 
Published: August 2010

AbstractWe report high-mobility rubrene single-crystal field-effect transistors with ionic-liquid electrolytes used for gate dielectric layers. As the result of fast ionic diffusion to form electric double layers, their capacitances remain more than 1.0 μF/cm2 even at 0.1 MHz. With high carrier mobility of 9.5 cm2/Vs in the rubrene crystal, pronounced current amplification is achieved at the gate voltage of only 0.2 V, which is two orders of magnitude smaller than that necessary for organic thin-film transistors with dielectric gate insulators. The results demonstrate that the ionic-liquid/organic semiconductor interfaces are suited to realize low-power and fast-switching field-effect transistors without sacrificing carrier mobility in forming the solid/liquid interfaces.
Modification of Semiconductor-Dielectric Interface in Organic Light-emitting Field-effect Transistors
Authors: Wang Yan , Kumashiro Ryotaro , Komatsu Naoya , Tanigaki Katsumi 
Published: August 2010

AbstractIn this work, ambipolar rubrene single crystal field-effect transistors (FETs) with PMMA modification layer and Au/Ca as electrodes were fabricated. The electron mobility was studied in these devices. PMMA modification layer on the surface of SiO2 is necessary for electron behavior. We found that the device with PMMA modified insulator and Au-Ca asymmetric metals possessed hole mobility and electron mobility of 1.27 and 0.017 cm−2/Vs, respectively. Furthermore, the shift of light emitting with applied gate voltage was observed in this device.