bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alteration of Si-B-Na-Al model glass in water at 90°C: experiments and thermodynamic modelling
Authors: Munier Isabelle , Crovisier Jean-Louis 
Published: April 2011

ABSTRACTAn attempt to model the alteration process of a model glass (Si-B-Al-Na), similar to the French reference SON68 glass, by using the geochemical code KINDIS, was developed. This simulation study was compared with experiments carried out in parallel: glass samples were placed at 90°C in pure water for 30 to 180 days, at two different S/V ratios (1 and 80 cm-1).The formation of the alteration layer was simulated by the precipitation of an ideal solid solution. The cases of oxides, hydroxides and metasilicates as end-members were tested. The considered solid solution always contains a siliceous end-member, which consists of amorphous silica, chalcedony or quartz.The relative thermodynamic stability of the chosen end-members (especially siliceous ones) influences directly the composition of the predicted gel and thus the composition of the solution. The results obtained by using chalcedony and hydroxides as end-members show a good agreement between the experimental and modelled silicon contents in solutions and in alteration gels, whatever the S/V ratio.The gel layer of the glass contains significant amounts of Na and Al, which are equimolar on average, what would probably correspond to the compensation of AlO4- charges by Na+.
Redox properties of MX-80 and Montigel bentonite-water systems
Authors: Lazo Cecilia , Karnland Ola , Tullborg Eva-Lena , Puigdomenech Ignasi 
Published: April 2011

ABSTRACTThe uptake of dissolved oxygen (O2) has been studied in bentonite suspensions in 0.1 M NaCl media at (25±2)°C. MX-80 and Montigel bentonites were used in concentrations varying from 18 to 73 g/L. The experiments were performed in a magnetically stirred closed glass vessel, in an N2-glove box. Redox potentials where measured with Pt-wires, and dissolved O2 was measured both with a membrane electrode and with an optode. The experiments with MX-80 show that dissolved O2 disappears in ∼5 days under these conditions. Redox potentials decreased from ∼ +500 to ∼ +125 mVSHE (versus Standard Hydrogen Electrode). The data for the Montigel bentonite show similar time scales for O2 uptake but lower redox potentials at the end of the experiments ∼ −175 mVSHE. Pyrite oxidation is perhaps not the main process for O2 uptake, as MX-80 contains 0.3% FeS2 while Montigel bentonite only has a negligible amount.
Interfacial Layer Effects in Ba1-xSrxTiO3 Thick Films prepared by Plasma Spray
Authors: Ahn Kipyung , Wessels Bruce W. , Sampath Sanjay 
Published: April 2011

ABSTRACTThe dielectric properties of high k dielectric thick films prepared by thermal spray were investigated. BaTiO3 and Ba0.68Sr0.32TiO3 thick films were deposited using plasma spray on Ag-Pd screen-printed alumina substrates. The sprayed films were predominantly polycrystalline but contained an amorphous second phase. The dielectric constants of the films decreased with decreasing film thickness in 10 ∼ 60 μm range. This was attributed to the presence of an interfacial layer between the film and the substrate as determined by capacitance measurements. The capacitance density of the interfacial layer was determined to be ∼ 2.7 nF/cm2. The capacitance density of the interfacial layer increased to 12 nF/cm2 after post heat treatment at 500 °C for 20 hours.
Characterization of Electrostatic Micromembrane Actuator Performance Using a Mass Probing Method
Authors: Wu Xingtao , Hui Jeremy , Kayatta Pat , Kenneth Dedeian , Young Mariam , Warde Cardinal 
Published: April 2011

ABSTRACTWe describe a mass probing technique for characterizing the electro-mechanical behavior of micromembrane array actuators under electrostatic loads. The technique utilizes one or more arrays of center-positioned posts as a joint-link between an array of micro membrane actuators and a top movable rigid mass plate to generate 1D motion of the top mass owing to motion transfer from the deformed membranes. The micromembrane actuator arrays are fabricated using a stacked architecture similar to MUMPs in which the poly-Si structure material is replaced by metal-over-polymer composite, and final release is accomplished by a dry etch of a-Si sacrificial material. The mass probing technique is implemented by hybrid integrating a thick (100∼650-μm), heavy, and rigid mass plate (with a polished surface as a reflective mirror) onto the membrane array in which individual membrane actuators have a center interface post to act as mechanical linkage. A preliminary test of a 40-um pitch membrane array shows a 1st natural frequency of 2.1MHz of the membrane actuator. This was scaled down to ∼50KHz by a 2.7mmx2.7mm 200-μm thick mass load weighting 3.3-mg. Ignoring the small membrane mass, the lumped spring stiffness is estimated to be ∼70-μN/μm per actuator (3248 40-μm actuators embedded beneath the probing mass). Thus, motion transfer principle from micro size actuators to macro size components was demonstrated.
Interface Adhesion and Reliability of Microsystem Packaging
Authors: Francis Marvin I. , Wadach Kellen , Walwadkar Satyajit , Cho Junghyun 
Published: April 2011

ABSTRACTFlip-chip technology is becoming one of the most promising packaging techniques for high performance packages. Solder balls are used as the connection technique in the flip-chip method and the connections are reinforced by filling in the spacing between the chip and substrate with underfill. The function of the underfill is to reduce the stresses in the solder joints caused by a coefficient of thermal expansion (CTE) mismatch. The presence of polymeric underfill material will, however, make the flip-chip packaging system susceptible to interfacial failure. Thus, the purpose of this study is to examine the interfacial delamination between the dissimilar materials in order to increase the reliability of the flip-chip interconnection method, and to understand the effect of underfill curing conditions on the interface adhesion. In particular, we use a linear elastic fracture mechanics (LEFM) approach to assess interfacial toughness. For this purpose, four-point bending testing is performed to determine a critical strain energy release rate, Gc. In addition, nano-indentation testing equipped with atomic force microscope (AFM) is employed to determine structure and properties of the underfill layer.
Application of FIB/SEM and TEM to Bit Failure Analyses in SRAM Arrays
Authors: Qin Wentao , Volinsky Alex , Rice Larry , Johnston Lorraine , Theodore David 
Published: April 2011

ABSTRACTMany microelectronic chips contain embedded memory arrays. A single SRAM bit-cell contains several transistors. Failure of any of the transistors makes the entire bit-cell inoperable. Dual-beam Focused Ion Beam (FIB) combines the slicing capability of FIB with in-situ SEM imaging. The combination offers unparalleled precision in looking for root causes of failures in microelectronic devices. Once a failure site is located, an FIB lift-off method can be used to prepare a TEM sample containing the area of interest. Further structural, elemental information can then be acquired from the failure site. We report here analyses of single and multiple bit failures in SRAM arrays carried out using FIB/SEM, and in two cases TEM imaging and EDS/PEELS. Root causes of bit failures including remnant seed-layer metal between stacked vias have been identified.
Formation of a Ba-Te Surface on GaAs
Authors: Boulais Kevin A. , Santiago Francisco , Long Karen J. , Gehman Victor H. 
Published: April 2011

ABSTRACTThe formation of a Ba-Te surface on GaAs has been investigated. The surface was created using molecular beam epitaxy (MRS). A GaAs (100) surface was first exposed to Te and characterized using x-ray photoelectron spectroscopy (XPS), reflective high energy electron diffraction (RHEED) and low energy electron diffraction (LEED). The Te-reacted surface was then exposed to BaF2 flux producing a second reaction. In this reaction, the BaF2 dissociated leaving barium on the surface but no fluorine. This is in contrast to the clean (no tellurium) GaAs (100) surface in which BaF2 has been shown to grow single crystal. Although high order exists during early stages of the Ba-Te growth, further exposure gives way to a polycrystalline form. This paper discusses the formation and analysis of the Ba-Te surface.
Potentiometric Detection of DNA Molecules Hybridization Using Gene Field Effect Transistor and Intercalator
Authors: Sakata Toshiya , Otsuka Hidenori , Miyahara Yuji 
Published: April 2011

ABSTRACTWe propose a new concept of a gene field effect transistor (FET) for detection of allele specific oligonucleotide hybridization, which is in principle based on charge density change at the gate insulator. The electrical characteristics of the gene FET were found to shift after specific binding of biomolecules at the surface of the gate insulator. Allele specific oligonucleotide hybridization and reaction between double-stranded DNA and intercalator were successfully detected with gene FETs because they have intrinsic charges in an aqueous solution. Ability to discriminate single nucleotide polymorphism (SNP) was also examined using the gene FET. Our results show that control of hybridization temperature and utilization of intercalator lead to more precise SNP analysis using the gene FET.
Nanocomposites with functionalized carbon nanotubes
Authors: Mhetre Shamal K. , Kim Yong. K. , Warner Steven. B. , Patra Prabir. K. , Katangur Phaneshwar , Dhanote Autumn. 
Published: April 2011

ABSTRACTThe main issues related with preparation of nanocomposites are dispersion, alignment and adhesion between carbon nanotubes and matrix. We are designing an approach where these issues are fully addressed. We combined a functionalization approach with in-situ technique of nanocomposites preparation. A good dispersion and intercalation of carbon nanotubes were observed in the prepared nanocomposites. A presence of strong interfacial region was also noted. It is also found that orientation of carbon nanotubes inside matrix can be done by mechanically stretching of nanocomposites. DSC analysis shows that inclusion of carbon nanotubes affects crystallization behavior of nylon 6 significantly and it is found that CNTs acts as nucleating agents.
Virtual Synthesis of Sub-Nanoscale Materials With Prescribed Physical Properties
Authors: Pozhar Liudmila A. , Yeates Alan T. , Szmulowicz Frank , Mitchel William C. 
Published: April 2011

ABSTRACTProperties of electronic energy spectra of several small virtual clusters (known as small quantum dots, or QDs) composed of In, Ga and As atoms are investigated for the further use in nanoheterostructure (NHS) units of pre-designed electronic properties. Modern quantum statistical physics methods relate these properties to electronic transport properties of such systems and therefore, lead to realization of a virtual (i.e., fundamental theory- based, computational) approach to synthesis of sub-nanoscale electronic materials with pre-designed electronic properties[1].
Microstructure of Precipitated Au Nanoclusters in TiO2
Authors: Wang C. M. , Shutthanandan V. , Zhang Y. , Baer D. R. , Thomas L. E. , Thevuthasan S. 
Published: April 2011

ABSTRACTGold nanoclusters dispersed in single crystal TiO2 (110) have been formed by 2MeV Au2+ implantation to an ion fluence of 1×1017 cm-2 at 300 K and 975 K followed by annealing at 1275 K for 10 hours. The morphological features, size and crystallographic orientation of the Au nanoclusters with respect to the TiO2 matrix have been investigated using conventional transmission electron microscopy and electron diffractions. In particular, the interface structure between the Au nanoclusters and TiO2 was investigated. Atomic structural model of interface between Au and TiO2 was established based on high-resolution transmission electron microscopy (HRTEM) imaging and HRTEM image simulations. Two types of orientation relationship can be identified, Au<110>//TiO2[001] and Au{111}//TiO2(200), and Au<110>//TiO2[001] and Au{111}//TiO2(110). Au clusters are faceted along Au{112}and Au{111} or Au{220} and Au{002} planes. The precipitated Au clusters show extensive (111) twins. These orientation relationships are the same for Au clusters grown on TiO2(110) surface, indicating that lowering interfacial energy to be a governing factor for setting the orientation relationship.
HSA-Cercanam®: A New Material with a Continuous Nanopore Network
Authors: Akash A. , Nair B. , Minnick K. , Wilson M. , Hartvigsen J. 
Published: April 2011

ABSTRACTA novel nano-ceramic material, called HSA-CERCANAM®, which has a very high surface area with a nanopore network has been developed. HSA-CERCANAM® can be casted in various shapes and forms resulting in a monolithic piece that has surface area as high as 80–100 m2/g. The surface area and the nanopore network of HSA-CERCANAM® remains stable at temperatures as high as 1000°C. Furthermore, the unique nature of HSA-CERCANAM® allows it to be casted on and around features, either sacrificial or permanent. Using sacrificial features, microchannels can be incorporated internally into the monolithic HSA-CERCANAM® piece in a simple, one-step process. Further, this monolithic ceramic component, which has an intrinsically high surface area and a nanopore network, can be infiltrated with a desired catalyst. This could offer clear technological advantages over currently available microreactors. The surface area, porosity, catalyst type and infiltration levels are some of the ways in which tailored microstructures can be realized in components such as mixers, heat exchangers, extractors, filters or reaction chambers thereby leading to highly efficient, multi-functional ceramic micro-devices.
A Model of New VUV NLO Materials Based on Borate: A Novel Noncentrosymmetric Borophosphate Compound Be3BPO7
Authors: He Zhangzhen , Moriyama Hiroshi 
Published: April 2011

ABSTRACTA favorable borate anionic group can be selected as the basic structural unit for VUV NLO materials, in terms of the properties of known inorganic NLO crystals and the features of their anionic groups, based on anionic group theory from SHG coefficients, UV absorption edge and moderate birefringence. Considering the coordination chemistry of atoms in some inorganic compounds, and the relationship between a noncentrosymmetric structural arrangement and the composition of compounds, a suitable theoretical model that aids the search for new VUV NLO materials has been proposed. The model compounds, formulated as MxA1,2(BO3)1,2Oy, may be prospective candidates for new VUV NLO materials considering their SHG coefficients, UV absorption edge, and moderate birefringence. The model suggests that investigation for a new VUV NLO material would be profitably conducted by focusing on boroberylate, boroaluminate, and borophosphate, on the basis of anionic group theory. For example, a novel noncentrosymmetric beryllium borophosphate compound, Be3BPO7 was synthesized by solidstate reaction. Microcrystalline Be3BPO7 has a hexagonal system and contains the BO3 anionic group as its basic structural unit, which should play an important role for SHG coefficients. In fact, Be3BPO7 powder was found to have a significant SHG effect.
In-situ Observation of Formation Processes of Anodic Porous Alumina on a Si Substrate Using Infrared Absorption Spectroscopy
Authors: Kimura Yasuo , Shiraki Hirokazu , Ishii Hisao , Ono Sachiko , Itaya Kingo , Niwano Michio 
Published: April 2011

ABSTRACTWe investigated formation processes of a porous anodic alumina film on a p-type silicon (Si) substrate using infrared absorption spectroscopy in the multiple internal reflection geometry (MIR-IRAS). We observed drastic IR spectral changes when porous anodic alumina film approached interfaces between an aluminum (Al) layer and a Si substrate. The intensity of the IR absorption peaks due to water (H2O) molecules and silicon oxides (SiO2) increased simultaneously with a spike of anodic current density. The IR spectral changes indicated that the penetration of electrolytes brought about inhomogeneous oxidation of a Si substrate surface. We observed that the arrangement of the SiO2 nanodots closely reflected that of pores of a porous anodic alumina film. IR absorption peaks due to porous anodic alumina finally disappeared. The formation of SiO2 nanodots on a Si substrate promoted penetration of electrolytes to peel the porous anodic alumina film off it.
MODELLING TWO–PHASE FLOW IN MICROFLUIDIC DEVICES
Authors: Menech Mario De 
Published: April 2011

ABSTRACTA phase–field method is used to model two–phase flow in microfluidic devices, where capillary and viscous stresses dominate over inertial forces. Dissipative and reactive couplings in the hydrodynamic equations are derived from a Cahn–Hilliard–van der Waals free energy, which accounts for the equilibrium thermodynamics of the fluid system, including phase behavior, interfacial tension and wetting properties. The singularities inherent to the free boundary description are smoothed out by the presence of a diffuse interface over which interfacial stresses are distributed, such that complex phenomena like droplet breakup and coalescence or contact line dynamics can be resolved numerically. The reliability of the scheme used to solve the discretized transport equations is tested against different benchmarks for free flow conditions. The model is then applied to the simulation of the flow of droplets in microdevices, resulting in a satisfactory agreement with the behavior observed in experiments.
INFLUENCE OF CONFINEMENT ON POLYMER-ELECTROLYTE RELAXATIONAL DYNAMICS
Authors: Zanotti J.-M. , Smith L.J. , Price D.L. , Saboungi M.-L. 
Published: April 2011

ABSTRACTConception and industrial production of viable high specific energy/power batteries is a central issue for the development of non-polluting vehicles. In terms of stored energy and safety, solid-state devices using polymer electrolytes are highly desirable. One of the most studied systems is PEO (polyethylene oxide) complexed by Li salts. Polymer segmental motions and ionic conductivity are closely related. Bulk PEO is actually a biphasic system where an amorphous and a crystalline state (Tg ≈ 213 K, Tm ≈ 335 K) coexist. To improve ionic conduction in those systems requires a significant increase of the amorphous phase fraction where lithium conduction is known to mainly take place. Confinement strongly affects properties of condensed matter and in particular the collective phenomena inducing crystallization. Confinement of the polymer matrix is therefore a possible alternative route to the impractical use of high temperature.Results of a quasi-elastic incoherent neutron scattering study of the influence of confinement on polyethylene oxide (PEO) and (PEO)8Li+[(CF3SO2)2N]− (or (POE)8LiTFSI) dynamics are presented. The nano-confining media is Vycor, a silica based hydrophilic porous glass (characteristic size of the 3D pore network ≈ 50 Å). As expected, the presence of Li salt slows down the bulk polymer dynamics. The confinement also affects dramatically the apparent mean-square displacement of the polymer. Local relaxational PEO dynamics is described KWW model. We also present an alternate model and show how the detailed polymer dynamics (correlation times and local geometry of the motions) can be described without the use of such stretched exponentials so as to access a rheology-related meaningful physical quantity: the monomeric friction coefficient.
Effect of Thin Film Confinement on the Transport Properties of Ultra-Thin Polymer Films
Authors: Singh Lovejeet , Ludovice Peter J. , Henderson Clifford L. 
Published: April 2011

ABSTRACTThe influence of film thickness and polymer molecular weight on the diffusion coefficient of a series of small molecule penetrants (including water, benzene, and trifluoroacetic acid) in thin films of two different model photoresist polymers (poly(p-hydroxystyrene) and bis-triflouromethyl carbinol substituted poly(norbornene)) has been studied using vapor sorption experiments via quartz crystal microbalance (QCM) methods. Diffusion coefficients for films ranging in thickness from approximately 1 μm to 50 nm were determined. It is observed that the diffusion coefficient of small molecules in a thin polymer film is a strong function of film thickness, and that the diffusion coefficient decreases drastically as film thickness is reduced below a critical thickness value. This critical thickness value is found to be a function of both the type of polymer used and the polymer molecular weight.
Improvement of Crystallization and Mechanical Properties of PLA by Means of Clay Nanocomposite
Authors: Okamoto Hirotaka , Nakano Mitsuru , Ouchi Makoto , Usuki Arimitsu , Kageyama Yuji 
Published: April 2011

ABSTRACTSome composite materials of poly (lactic acid) (PLA) with organophilic clays and an organic crystal accelerator (OCA) were prepared by melt compounding method to improve the rate of crystallization and mechanical properties, especially heat distortion temperature (HDT). The PLA/clay nanocomposite with 2.9wt% of finely dispersed organophilic clay and 1wt% of the OCA showed an exothermic peak corresponding to its crystallization at 1.9 minutes in the isothermal measurement of DSC at 100°C from its molten state, although PLA itself did not show a clear peak in the same procedure. Crystallized specimens of the nanocomposite were well obtained by injection molding when the hold time was set at more than 90 seconds. The HDT of the specimens that were held for more than 120 seconds in the mold exceeded 120°C. It is about 65°C higher than amorphous PLA. The crystallized specimen with 1wt% of the clay showed higher tensile modulus and Izod impact strength than the amorphous one.
The Microstrain Generation in Cryomilled Nickel by Impurity Nitrogen Atoms
Authors: Chung Kyung H. , Lavernia Enrique J. 
Published: April 2011

ABSTRACTThe residual microstrains in cryomilled Ni powders, processed under various cryomilling conditions, are measured by XRD and analyzed using a single line approximation (SLA) method. The results show that the average residual microstrains are in the range of 2×10-3 ∼ 6×10-3, and the residual microstrain on the (200) plane is higher than those on the other planes by 33 %. The measured microstrain is proposed to evolve from the introduction of N as impurity atoms in Ni lattice may be attributed to the evolution of the residual microstrain. The N atoms tend to stay in the octahedral sites of Ni, and the diameter of N atom is larger than that of the octahedral site of Ni by 48 %. Accordingly, a lattice strain field is expected around interstitial N atoms that are located at octahedral sites. By comparing the crystal structure around the octahedral site of Ni with that of Ni3N structure, the lattice strains are estimated to be in the range of 5 ∼ 15 %. The results show that the (200) plane has the lattice strains that are two times higher than those in other planes, and this is argued to be the reason for the measured anisotropy of residual microstrain in Ni after cryomilling.
Surface porosity development on metal substrates by helium implantation and annealing.
Authors: Escobar Galindo R. , van Veen A. , Schut H. , Evans J.H. , Fedorov A.V. , Hou P.Y. , de Hosson J.Th.M. 
Published: April 2011

ABSTRACTThe effects of helium implantation parameters and heating schemes on the formation of surface porosity have been studied. Confinement of the implanted helium by a coating on the metal leads to a prolonged development of the bubble structure. Finally, delamination and blistering occurs and rather open surface structures remain.