bluuebunny/crossref_metadata_2025_split huggingface dataset:
Threshold strength and residual stress analysis of zirconia–alumina laminates
Authors: Moon Haksung , Bahk Je-Hyeong , Lange Fred F. 
Published: August 2007

Abstract
We dedicate this work to Wolfgang Pompe, a very good friend and a good friend of the Materials Faculty at UCSB where he and his wife, Gisela, shared their lives and fellowship.
Three different zirconia – alumina laminates, AZ50, AZ80, and AZ95, were fabricated via tape-casting thick Zr(3Y)O2 layers, dip-coating the zirconia tapes in a slurry containing a mixture of zirconia and alumina, stacking and bonding the coated zirconia tapes, followed by densification. Each composite had a different compressive stress by using different mixtures of alumina and zirconia (the number associated with each composite system refers to the volume fraction of alumina in the thin, compressive layers). After densification, the Zr(3Y)O2 layers were ∼ 425 μm thick, and the thin alumina/zirconia layers were 60 ∼ 65 μm thick. The threshold strengths, below which the probability of failure is zero, were determined to be 255 ± 8 MPa, 311 ± 7 MPa, and 421 ± 12 MPa for AZ50, AZ80, and AZ95 laminates, respectively. These values are about 60 ∼ 70 % of those calculated from a previously reported function. The surface and interior stresses were determined using a finite element analysis. The compressive stresses of the outer alumina/zirconia layers were determined using a piezospectroscopy method. The surface stresses for the thick zirconia layers were estimated using an indentation – crack length relation. The piezospectroscopy, analytical and finite element analysis results for the outer compressive layer were in good agreement. But, the finite element analysis showed that the compressive stress component on the surface of the compressive layers was approximately half the value of the biaxial compressive stresses deep within the thin, compressive layers. It appears that the much smaller compressive stresses on the surface of the compressive layers is one important factor that resulted in the lower threshold strength than predicted by the previously developed function used to estimate the threshold strength.
Crack formation in surface layers with strain gradients
Authors: Romanov Alexei E. , Beltz Glenn E. , Speck James S. 
Published: August 2007

Abstract
The problem of crack formation in surface layers where a linear profile of elastic strain prevails through the thickness of a layer is investigated. Such strain gradients can be generated, for example, in graded alloy semiconductor layers or due to specific stress relaxation mechanisms in lattice mismatched layers or previously unanticipated dislocation-related strain gradients. The operation of the relaxation mechanisms related to threading dislocation inclination and leading to the strain gradients in nominally compressed Al
x
Ga1 – x
N layers grown on buffer layers with smaller lattice constants is discussed. A fracture mechanics model is developed for the calculation of the stress intensity factor of mode I cracks initiated at the surface of the layer exhibiting a linear strain dependence. The critical layer thickness for crack formation in such a gradient elastic field has been found in the framework of this fracture mechanics model. Results of the modeling are compared with experimental observations of crack onset in nominally compressed layers of Al
x
Ga1−x
N semiconductors. Good agreement between the model predictions and the experimental data is found.
Threshold strength prediction for laminar ceramics from bifurcated crack path simulation
Authors: Bahr Hans-Achim , Pham Van Bac , Weiss Hans-Jürgen , Bahr Ute , Streubig Matthias , Balke Herbert , Ulbricht Volker 
Published: August 2007

AbstractThin compressive layers sandwiched between thicker tensile layers in laminar ceramics can stop unstable cracks. As shown by Lange and co-workers, the arrested crack propagates stably through the compressive layer under increasing load until a critical load or threshold strength is reached. In 4-point flexural loading tests, cracks can bifurcate after entering into the compressive layer. This paper presents finite element simulations of bifurcated crack paths and threshold strength prediction in two-dimensional approximation. In rather good agreement with experiments the calculated threshold strength increases with compression and is higher with bifurcated cracks than with straight cracks, and higher with loading axis parallel to the laminar plane than normal to it.
In-situ measurement of local strain partitioning in a commercial dual-phase steel
Authors: Ososkov Yuriy , Wilkinson David S. , Jain Mukesh , Simpson Todd 
Published: August 2007

Abstract
This paper presents the results of an in-situ Scanning Electron Microscopy study of the local strain partitioning between ferrite- and martensite-rich regions in a commercial dual-phase steel. A Scanning Electron Microscopy tensile micro-stage, coupled with strain measurement methodologies based on gold micro-grids and digital image correlation, has been used to measure inhomogeneous strain fields at the micron scale. It has been found that when martensite is distributed non-uniformly, local strain partitioning depends significantly on the local spatial phase distribution and morphology. Strain distribution maps can be developed which provide valuable information about local strain paths for both phases. The results suggest that a rather detailed description of the two-phase microstructure of such materials is needed in order to fully understand their mechanical behaviour.
Chemical Amplification of a Triphenylene Molecular Electron Beam Resist
Authors: Zaid H. M. , Robinson A. P. G. , Palmer R. E. , Manickam M. , Preece J. A. 
Published: August 2007

AbstractMolecular resists, such as triphenylene derivatives, are small carbon rich molecules, and thus give the potential for higher lithographic resolution and etch durability, and lower line width roughness than traditional polymeric compounds. Their main limitation to date has been poor sensitivity. A new triphenylene derivative molecular resist, with pendant epoxy groups to aid chemically amplified crosslinking, was synthesized and characterized. The sensitivity of the negative tone, pure triphenylene derivative when exposed to an electron beam with energy 20 keV was ∼ 6 × 10–4 C cm–2, which increased substantially to ∼ 1.5 × 10–5 C cm–2 after chemical amplification (CA) using a cationic photoinitiator. This was further improved, by the addition of a second triphenylene derivative, to ∼ 7 × 10–6 C cm–2. The chemically amplified resist demonstrated a high etch durability comparable with the novolac resist SAL 601. Patterns with a minimum feature size of ∼ 40 nm were realized in the resist with a 30 keV electron beam.
Novel Percolation Mechanism in PMMA Matrix Composites Containing Segregated ITO Nanowire Networks
Authors: Capozzi C. J. , Gerhardt R. A. 
Published: August 2007

AbstractPoly(methyl methacrylate) (PMMA)/indium tin oxide (ITO) nanocomposites were prepared by mechanical mixing and compression molding in order to study the properties and microstructure of the composites. The composites were examined by optical and scanning electron microscopy, impedance spectroscopy, and UV‐VIS spectrophotometry. It was observed that upon compaction of the powders above the glass‐transition temperature of the matrix, the PMMA transforms from spherical to polyhedral‐shaped, and develops sharp edges and flat faces. The ITO nanoparticles do not penetrate the polymer particles, resulting in a novel segregated network microstructure. Excellent correlation between the electrical, optical, and microscopy data also provide good insight about the behavior of the filler as the content is increased in the nanocomposites. There is strong evidence that the ITO nanoparticles are extensively displaced during compaction as the PMMA powders become polyhedral‐shaped. Our results indicate that percolation occurs due to the ITO forming a continuous network along the edges of the faceted PMMA particles. The ITO nanoparticles do not appear on the faces of the PMMA particles until after a percolation path has formed and a marked increase in electrical conductivity has occurred. This behavior significantly diverges from previous models for segregated network microstructures which proposed that percolation occurred as the result of limited displacement of the filler during compaction of the mixed powders.
Palladium Nanowire from Precursor Nanowire: Crystal‐to‐Crystal Transformation via In Situ Reduction by Polymer Matrix
Authors: Porel S. , Hebalkar N. , Sreedhar B. , Radhakrishnan T. P. 
Published: August 2007

AbstractPrecursor nanowires of potassium palladium(II) chloride crystallized inside a poly(vinyl alcohol) film are reduced to palladium nanowires by the polymer itself under mild thermal annealing. The chemical reaction occurring in situ inside the polymer film, including byproduct formation, is investigated through electronic absorption and X‐ray photoelectron spectroscopy together with atomic force and electron microscopy. The overall process can be described as a novel case of crystal‐to‐crystal transformation at the nanoscopic level. Optical limiting characteristics of the nanowire‐embedded polymer film are explored. The fabrication procedure developed, involving chemistry inside a polymer matrix mediated by the polymer, opens up a convenient route to the fabrication of free‐standing metal nanowire‐embedded thin films.
Synthesis and physicochemical studies of ferrocene‐containing materials
Authors: Iqbal Naseer , Khan Muhammad Saif ullah , Adnan Saeed M. , Akhter Zareen 
Published: August 2007

AbstractLow‐temperature solution‐phase polycondensation of 1,1′‐ferrocenedicarboxylic acid chloride with newly synthesized aromatic diamines was carried out in tetrahydrofuran in the presence of triethylamine to form several new organometallic aromatic polyamides containing ferrocene units. The organometallic aromatic polyamides derived were in good yields ranging from 75 to 80%, amorphous with melting temperatures of > 350 °C. The monomers and the resulting polymers were characterized by their physical properties, elemental analysis,1H NMR and FTIR spectroscopy. The differential scanning calorimetry and thermogravimetric studies of the resulting aramids were also carried out. All the polymers were insoluble in common organic solvents. However, all dissolved in concentrated H2SO4 forming reddish brown solutions. Their glass transition temperatures were quite high, which is characteristic of aramids. They were also stable up to 450 °C with 10% mass losses (14–23%) recorded in the range 400–470 °C. The activation energies for decomposition of each aramid were also calculated using the Horowitz and Metzger method. All polymers showed reduced solution viscosities in concentrated sulphuric acid, which may be attributed to non‐Newtonian behavior. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and characterization of poly(isoprene‐b‐carbonate)s derived from hydroxytelechelic polyisoprenes
Authors: Derouet Daniel , Nguyen Tran Minh Giao , Brosse Jean‐Claude 
Published: August 2007

AbstractThe purpose was to develop a procedure to synthesize copolymer incorporating flexible polyisoprene blocks and rigid polycarbonate blocks, to obtain thermoplastic elastomer characteristics. The choice was directed towards poly(isoprene‐b‐carbonate) structures by using a condensation mechanism consisting to create carbonate functions by reaction between an organic dihalide and a diol carried out in presence of potassium carbonate, and by using hydroxytelechelic polyisoprenes as reagents. Polycarbonates of various structures were synthesized, followed by that of the required poly(isoprene‐b‐carbonate)s. The synthetic procedure thus developed has the advantage to allow a control of the structure and the composition of the copolymer according to the nature and the proportions of the reagents involved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
New segment in new theory of polymer
Authors: Matsushita Yahachiro 
Published: August 2007

AbstractMelting temperature (Tm) can be divided in two steps of (Tm–Tg) and Tg in the glass transition temperature. There are respective segments in both steps. The difference of elongation, which causes a separation between two arrays in segment, is of two kinds: mechanical and thermal. Tg is given as disappearance of the segment, which would not be so if the kind of elongation were the same. A prefix of micro at Brown on Tg is meaningless, because the segment can be explained from a different point view the phenomena shown as a sign of melting at Tg. Tg between polymer and components of CC bond in repeat unit is given as Tg = Σ[1/n(1%)/ai] = Σ[(1/n)Tgi], where α is the linear coefficient of thermal expansion, n is the total number of components, Tgi, αi is the value of component i. A magnitude of elongation of component Ci is given as αi with the result, which the side chains have functioned like a weighting function. Strength of linear polymer is connected with the total number of segments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Long‐Chain Polyamines (LCPAs) from Marine Sponge: Possible Implication in Spicule Formation
Authors: Matsunaga Satoko , Sakai Ryuichi , Jimbo Mitsuru , Kamiya Hisao 
Published: August 2007

AbstractTwo distinct marine organisms, diatoms and sponges, deposit dissolved silicates to construct highly architectural and species‐specific body supports. Several factors such as proteins, long‐chain polyamines (LCPAs), or polypeptides modified with LCPAs are known to be involved in this process. The LCPAs contained in the silica walls of diatoms are thought to play pivotal roles in the silica deposition. In sponges, however, a protein called silicatein and several other proteins have been reported to be the factors involved in the silica deposition. However, no other factors involved in this process have been reported. We have identified the LCPAs from the marine sponge Axinyssa aculeata and present here some evidence that sponge‐derived LCPAs can deposit silica and that the LCPA derivatives are associated with spicules. The results indicate a common chemistry between sponges and diatoms, the two major players in the biological circulation of silicon in the marine environment. A wide variety of organisms are known to utilize silica in their biological processes. Polyamines or other functional molecules might be involved, in combination with proteins, in their biosilicification process.
Open, reconfigurable cytometric acquisition system: ORCAS
Authors: Naivar Mark A. , Parson Jimmie D. , Wilder Mark E. , Habbersett Robert C. , Edwards Bruce S. , Sklar Larry , Nolan John P. , Graves Steven W. , Martin John C. , Jett James H. , Freyer James P. 
Published: August 2007

AbstractA digital signal processing (DSP)‐based digital data acquisition system has been developed to support novel flow cytometry efforts. The system flexibility includes how it detects, captures, and processes event data. Custom data capture boards utilizing analog to digital converters (ADCs) and field programmable gate arrays (FPGA) detect events and capture correlated event data. A commercial DSP board processes the captured data and sends the results over the IEEE 1394 bus to the host computer that provides a user interface for acquisition, display, analysis, and storage. The system collects list mode data, correlated pulse shapes, or streaming data from a variety of detector types using Linux, Mac OS X, and Windows host computers. It extracts pulse features not found on commercial systems with excellent sensitivity and linearity over a wide dynamic range. List mode data are saved in FCS 3.0 formatted files while streaming or correlated waveform data are saved in custom format files for postprocessing. Open, reconfigurable cytometric acquisition system is compact, scaleable, flexible, and modular. Programmable feature extraction algorithms have exciting possibilities for both new and existing applications. The recent availability of a commercial data capture board will enable general availability of similar systems. © Published 2007 Wiley‐Liss, Inc.
Test meal intake in obese binge eaters in relation to impulsivity and compulsivity
Authors: Galanti Kochavi , Gluck Marci E. , Geliebter Allan 
Published: August 2007

AbstractObjective:Studies have linked increased impulsivity and compulsivity with bulimia nervosa (BN). Less is known about this relationship in binge eating disorder (BED).Method:Seventy‐nine overweight participants (28 male, 65 females) were classified as BED (n = 22), BE (Subthreshold BED, not meeting full criteria for BED) (n = 21), and non‐BED (n = 36). Following an 8‐hr fast, participants completed psychological scales to assess impulsivity, compulsivity, and depression. They then consumed a liquid test meal until extremely full.Results:Test meal intake (TMI) was significantly greater for both BED and BE than non‐BED participants. Impulsivity and depression scores were significantly higher in BED and BE than in non‐BED participants. Men had significantly higher compulsivity scores than women. Impulsivity correlated significantly with TMI, accounting for 16% of the variance.Conclusion:There was greater impulsivity in BED and BE, compared with non‐BED. Moreover, impulsivity was the best predictor of TMI, and may play a larger role in BE than previously realized. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
A New Approach to Novel Cluster Compounds of Lead(II) Phosphonates
Authors: Du Zi‐Yi , Xu Hai‐Bing , Li Xiu‐Ling , Mao Jiang‐Gao 
Published: August 2007

AbstractFive new lead(II) sulfonate‐phosphonates, namely [Pb3(L)2(H2O)2]·4H2O (1), [Pb(HL)(phen)]·H2O (2), [Pb6(L)4(phen)8]·3H2O (3), [Pb6(L)4(phen)10]·2H2O (4), and [Pb6(L)4(4,4′‐bipy)(H2O)2]·2H2O (5; H3L = m‐HO3S‐C6H4‐PO3H2, phen = 1,10‐phenanthroline, 4,4′‐bipy = 4,4′‐bipyridine) have been prepared and structurally characterized. Compound 1 features a novel 3D framework in which 1D chains of Pb3O4 cluster units are further bridged by sulfonate‐phosphonate ligands, whereas compound 2 features a layer structure in which 1D chains of Pb2O4 clusters are further bridged by sulfonate‐phosphonate ligands. Compounds 3 and 4 represent the first zero‐dimensional lead(II) phosphonates and feature novel isolated hexanuclear lead(II) clusters in which six PbII ions are bridged by two tetradentate and two pentadentate phosphonate groups. Compound 5 features a 3D framework that is similar to that in compound 1 despite the different coordination modes for some sulfonate groups of the ligands. The main difference is that an aqua ligand in compound 1 is replaced by a nitrogen atom of the 4,4′‐bipy ligand, which results in the splitting of the large cavities in compound 1 into two small apertures in compound 5. Compounds 1 and 5 exhibit strong broad blue fluorescent emission bands at 398 and 420 nm, respectively.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Effect of Deprotonation of a Benzimidazolyl Ligand on the Redox Potential and the Structures of Mononuclear Ruthenium(II) Complexes
Authors: Sun Hongfei , Wang Mei , Jin Kun , Ma Chengbing , Zhang Rong , Sun Licheng 
Published: August 2007

AbstractA monoruthenium(II) complex of the benzimidazolyl ligand and its deprotonated counterpart were prepared and structurally characterized. The reversible protonation/deprotonation process of the ancillary ligand switches the redox potential of the ruthenium(II) core from 0.69 to 0.26 V vs. Ag/AgNO3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Asymmetric Induction by a Remote Chiral Substituent – Computationally Determined Stereodifferentiation in Michael Additions of α‐Lithiated Allyl Sulfones
Authors: Belostotskii Anatoly M. , Albeck Amnon , Hassner Alfred 
Published: August 2007

AbstractThe mechanism of stereoselectivity has been elucidated for the formation of two stereogenic centers in the products of Michael addition to ethyl crotonate by lithiated α‐anions of allylic sulfones bearing a remote chiral N‐substituent. In order to single out reactive carbanion structures, their conformational analysis was performed by ab initio calculations, finally at the B3LYP/6‐31+G(d) level. Low‐energy reactant structures were aligned taking intermolecular steric contacts into account. It appeared that only two cyclic conformers of the sulfone nucleophile in which the Li cation is chelated by the anionic carbon, as well as the S=O and NH moieties, are sterically accessible to the crotonate approach. Chiral discrimination of one of these conformers is due to an additional Li–π interaction provided by the remote Ph group of the N‐substituent. The enantioselectivity for the formation of the second stereocenter is due to a different asymmetry of the molecular electrostatic potential (calculated ab initio) in nucleophile–electrophile interactions. Thus, the observed diastereoselectivity is the result of a Ph–Li+ interaction, as well as a combination of steric and electrostatic factors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Short and Efficient Synthetic Strategy for the Total Syntheses of (S)‐(+)‐ and (R)‐(–)‐Plakolide A
Authors: Mohapatra Debendra K. , Pramanik Chinmoy , Chorghade Mukund S. , Gurjar Mukund K. 
Published: August 2007

AbstractConcise and efficient total syntheses of anticancer agents (S)‐(+)‐Plakolide A and (R)‐(–)‐Plakolide A were accomplished in eight steps and an overall yield of 39 % starting from geraniol. The key steps in our strategy are Sharpless asymmetric epoxidation, double elimination, and Stille coupling reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Domino Knoevenagel/1,6‐Heteroelectrocyclization Sequence to Access Phosphono‐2H‐thiopyrans
Authors: Riu Antonella , Harrison‐Marchand Anne , Maddaluno Jacques , Gulea Mihaela , Albadri Hashim , Masson Serge 
Published: August 2007

AbstractKnoevenagel‐type condensation reactions between phosphonodithioacetate 1 and α,β‐unsaturated aldehydes 2 directly afford 5‐phosphono‐substituted 2H‐thiopyrans 4. Use of heteroaromatic aldehydes allows the consecutive heteroelectrocyclization of the triene intermediate 3, provided that the aromatic character of the C5–C6 double bond is sufficiently decreased, which is the case for electron‐deficient indolenuclei. This Knoevenagel/1,6‐heteroelectrocyclization sequence represents a new domino process.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Photoacoustic detection of dissolved gases in transformer oil
Authors: Yun Yuxin , Chen Weigen , Wang Youyuan , Pan Chong 
Published: August 2007

AbstractThis paper investigates the applications of photoacoustic spectrometry (PAS) to analyze dissolved gases in transformer oil. An inexpensive experimental device with an electric pulse infrared light and six filters has been developed to detect six main fault gases in transformer oil, namely, CH4, C2H6, C2H4, C2H2, CO, and CO2. The method of choosing the characteristic wavelengths for the above six fault gases is discussed in detail. A weighted least‐square error method is proposed to analyze the measured data and to determine the component concentrations of dissolved gas in oil. Two sample sets of gas mixtures are analyzed by the experimental device for the purpose of verification. The PAS measurements are compared with the true values and the values measured by a conventional gas chromatograph (GC) method. The comparison results show that PAS is an effective way of analyzing dissolved gases in transformer oil, which exhibits some advantages in the gas detection such as consuming no gas, separating no gas, high accuracy, high stability, and rapid measurements. Copyright © 2007 John Wiley & Sons, Ltd.