bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization and physical properties of CoCl2 filled polyethyl‐methacrylate films
Authors: Abdelrazek E.M. , Elashmawi I.S. 
Published: May 2008

AbstractPure polyethyl‐methacrylate (PEMA) and PEMA filled with CoCl2 films were prepared by casting method. The structure and characterization of these film composites were investigated using Fourier transform infrared analysis (FTIR), optical spectra (UV), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and DC electrical conductivity. FTIR was used to identify the structural variations due to changing CoCl2 concentration. The assigned conjugated double bonds suggested the presence of polarons and bipolarons in the polymeric matrix. The shift of some bands manifested the specific interaction in PEMA matrixes and the filler. XRD reveals the presence of some crystalline phase in PEMA matrixes. The degree of crystallinity increase with increasing CoCl2 and there is no significant change on the halos center but it has become less obvious. Optical absorption measurements reveal that CoCl2 filler influences the optical energy gap. TGA data clarified that addition of CoCl2 to PEMA films enhances the thermal stability of PEMA. The activation energy decreases with increase in CoCl2 content. The electrical properties were studied using DC electrical conductivity. The electrical measurements revealed a nearly monotonic behavior of electrical conductivity as CoCl2 content increased. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Preparation and characterization of biodegradable waterabsorbent PAN/SS nanocomposite
Authors: Samal Bijayashree , Rana Pradeep Kumar , Sahoo Prafulla Kumar 
Published: May 2008

AbstractPolyacrylonitrile (PAN)/sodium silicate (SS) nanocomposite was prepared via nonconventional emulsion method using an in situ developed transition metal complex Cu(II)/glycine taking ammonium persulfate (APS) as initiator, with a novel motive of converting hydrophobic homopolymer PAN into hydrophilic nano material via nanotechnology by the inclusion of SS to the homopolymer. UV–visible spectral analysis was carried out which revealed various interactions between the in situ developed complex with other reaction components. The formation of the PAN/SS nanocomposite was confirmed by infrared spectra (IR). Furthermore, as evidenced by transmission electron microscopy (TEM), the composite so obtained was found to have nano scale structure. X‐ray diffraction (XRD) was carried out suggesting that the silicate layers were exfoliated during the polymerization process. An increase in the thermal stability for the developed nanocomposite was recorded by thermogravimetric analysis (TGA). Surprisingly, it was also found that the PAN/SS nanocomposite showed considerable amount of waterabsorbency and was biodegradable as tested by activated sludge and cultured media and further confirmed by scanning electron microscopy (SEM). POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Synthesis and characterization of montmorillonite/polypyrrole nanocomposite
Authors: Han Yongqin 
Published: May 2008

AbstractA novel montmorillonite (MMT)/polypyrrole (PPy) nanocomposite (MPN) with high electrical conductivity and thermal stability has been synthesized via in‐situ polymerization. The surface morphology, characterization, thermal stability, and electrical conductivity have been tested by scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and four‐probe methods, respectively. SEM results show that the antenna‐like PPy deposits on the layer surface of MMT. FTIR and XRD analyses show that there is interaction between MMT and PPy. The nanocomposite has high electrical conductivity (4 S/cm), eight orders of magnitude higher than that of pristine MMT. The thermal stability of MPN is higher than the pure PPy as well as the mixture of MMT and PPy (MMP). POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Numerical modeling of the impact response of fiber–metal laminates
Authors: Guan Z.W. , Cantwell W.J. , Abdullah R. 
Published: May 2008

AbstractThis article models the impact response of fiber–metal laminates (FMLs) based on a polypropylene (PP) fiber/PP matrix composite and two types of aluminum alloy. Here, a finite element analysis is used to model the impact behavior of FMLs at velocities up to 150 m/s. The PP‐based composite was modeled as an isotropic material with a specified tensile cut‐off stress to allow for the automatic removal of failed elements. The aluminum was modeled as an elasto‐plastic material with a specified shear failure strain and a tensile failure cut‐off stress. The deformed response of the structures and the resulting failure modes were compared with the experimental data. The variation of the maximum permanent displacement versus normalized impact energy was also predicted and compared with the impact test data and good agreement was observed. Finally, the decay of the kinetic energy of the projectile with time was determined for each of the targets and used to characterize their impact resistance. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Recurrent pulmonary alveolar proteinosis secondary to agammaglobulinemia
Authors: Patiroglu Türkan , Akyıldız Başak , Patiroglu Tahir E. , Gulmez Inci Y. 
Published: May 2008

AbstractPulmonary alveolar proteinosis (PAP) is characterized by the accumulation of surfactant derived material in the lung of patients. PAP is rare in children. The patient presented with respiratory failure. In the history she was diagnosed with agammaglobulinemia at 8 months of age and has been treated by IVIG once in a month. She had two pulmonary alveolary proteinosis attacks before. Chest X‐ray showed bilateral diffuse infiltrates. Initial diagnosis were pneumonia, ARDS, and lung edema. Whole‐lung lavage revealed lipoproteinaceous material similar to surfactant. This findings and high level of LDH was as evaluated pulmonary alveolary proteinosis. She discharged from the hospital without any respiratory complication on the ninth day. This is the first case report recurrent PAP associated with agammaglobulinemia. Pediatr Pulmonol. 2008; 43:710–713. © 2008 Wiley‐Liss, Inc.
Theoretical study of the optical response of the adsorption of Sb on the GaAs(110) surface
Authors: Mendoza Bernardo S. , Arzate N. , Vázquez‐Nava R. A. 
Published: May 2008

AbstractA theoretical study of the optical response of the adsorption of Sb atoms on the clean GaAs(110) surface is presented. The reflectance anisotropy spectroscopy (RAS) spectrum is calculated and analysed as a function of Sbcoverage. To capture some of the possible dynamical processes of Sb sub‐monolayer growth, a 1 × 3 unit cell is considered whose equilibrium geometry has been obtained by performing an ab‐initio pseudopotential calculation with the use of density functional theory within the local density approximation. The RAS is calculated via the ab‐initio scheme and also by using a semiempirical tight binding formalism. Some trends in the RAS spectra are identified as the clean surface is partially covered by Sb until the one monolayer coverage is achieved. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab‐initio optical spectra of complex systems
Authors: Cannuccia E. , Pulci O. , Palummo M. , Garbuio V. , Sole R. Del 
Published: May 2008

AbstractWe review the theoretical framework of ab‐initio excited state properties calculations showing the application of these methods to systems of different dimensionality. Many body perturbation theory within the GW approximation of the self energy for the calculation of electronic band structures is presented and applied to liquid water. The Bethe Salpeter equation for the computation of optical properties is illustrated and used for the case of surfaces and liquid water. An alternativemethod for the calculation of optical properties, the Time Dependent Density Functional Theory, is also briefly illustrated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomistic structure of Si atoms agglomerated nearby a stacking fault in a commercial GaAs:Si
Authors: Ohno Y. , Taishi T. , Yonenaga I. , Takeda S. 
Published: May 2008

AbstractPoint defects nearby a Frank‐type stacking fault in a commercial GaAs:Si wafer (with the Si concentration of about 1018 cm–3) were examined by ultrahigh‐vacuum cross‐sectional scanning tunneling microscopy (UHVXSTM). The defects were identified as pairs of a Si donor and a Ga vacancy. Even though the pairs were electrically neutral, the Si donors in the pairs might be active when they were in the bulk crystal, since the Ga vacancies in the pairs were considered to be introduced after the UHV‐XSTM specimen preparation. The Si donors might be agglomerated towards the stacking fault, since the Si concentration nearby the stacking fault was rather high in comparison with the surrounding region. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interactions between coherent optical phonons and excitonic quantum beats in GaAs/AlAs multiple quantum wells: strategy for enhancement of terahertz radiation from coherent optical phonons
Authors: Nakayama M. , Mizoguchi K. 
Published: May 2008

AbstractWe have investigated the dynamical properties of coherent longitudinal optical (LO) phonons and excitonic quantum beats in GaAs/AlAs multiple quantum wells with various layer thicknesses, utilizing a reflection‐type pump‐probe technique and an optical gating method with a photoconductive dipole antenna. It is found that the pump‐probe signal of the coherent GaAs‐like LO phonon is markedly enhanced under the energy‐resonance condition of the LO phonon and the quantum beat due to the fundamental heavy‐hole and light‐hole excitons. This enhancement is caused by the coupling between the coherent LO phonon and excitonic quantum beat via the longitudinal polarization; namely, the quantum beat acts as a driving force for the coherent LO phonon. On the basis of this finding, we have demonstrated that the terahertz radiation from the coherent LO phonon is considerably intensified at room temperature by the longitudinal polarization coupling described above. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electromodulated optical properties of the silver/pentacene/ITO thin film structure
Authors: Lu C. R. , Shih R. C. , Hsu H. K. , Chou W. Y. , Mai Y. S. , Chu S. W. , Lin S. Y. 
Published: May 2008

AbstractElectromodulated optical responses of the silver/pentacene/ITO thin film structures were characterized at various biases and temperatures. The optical transitions were perturbed by the energy shifts of the electronic states due to Stark effect induced by the modulation electric field. The modulated spectrum is strongly enhanced in the spectral regions involving the fundamental transitions and composed of the first derivatives of the unmodulated lineshapes. The field‐induced change of the transmission increases with the increasing modulation voltage. The transition energies of the silver/pentacene/ITO system can be derived from the peak positions in the electromodulated spectrum. As the temperature is increased from 25 K, the modulated transmission signal is also increased, and becomes non‐monotonous as the temperature is further increased. The transition energies involving the pentacene molecular states remain almost constant as the temperature varies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electro‐modulation enhancement in the InGaNAs/GaAs quantum well structures
Authors: Lee J. R. , Lu C. R. , Liu H. L. , Lin H. H. , Sun L. W. 
Published: May 2008

AbstractElectrooptical properties of InGaNAs/GaAs quantum well structures were investigated by photoreflectance spectroscopy. The MBE grown structures consist of a central InGaNAs well, GaAs barriers, and GaAsN strain compensating buffer layers of different thickness. More quantum states and extended wave functions in the system with strain relief GaAsN barriers due to broader and lower confinement profile. Particular electro‐modulated spectral features corresponding to excitonic interband transitions are enhanced. Compared with the numerically calculated quantum state energies and wave functions, the electromodulation enhanced transitions were those involving quantum states with wave functions distribute in wider regions and extend more from the InGaNAs well into the space charge region near interfaces. It was the internal electric field near the heterointerfaces strongly enhanced the electro‐modulation efficiency. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and characteristics of a Pt/MgxZn1–xO Schottky photodiode on a ZnO single crystal
Authors: Endo H. , Sugibuchi M. , Takahashi K. , Goto S. , Hane K. , Kashiwaba Y. 
Published: May 2008

AbstractThe photoresponse of a Pt/MgxZn1–xO Schottky photodiode using a (0001) ZnO single crystal substrate grown by the hydrothermal growth method is described in this report. MgxZn1–xO thin films were prepared by a reactive RF magnetron sputtering method on the Zn‐face of the ZnO single crystal substrate. The prepared MgxZn1–xO thin films had a band gap of 4.1 eV. The fabricated Schottky photodiode had high responsivity of 0.034 A/W at the wavelength of 250 nm, and the responsivity ratio at wavelength of 250 nm and 550 nm was of the order of 4. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
QSAR Study on Piperidinecarboxamides as Antiretroviral Agents: An Insight Into the Structural Basis for HIV Coreceptor Antagonist Activity
Authors: Dessalew Nigus 
Published: May 2008

AbstractChemokines receptors have emerged as important drug targets for the development of agents against the Human Immunodeficiency Virus (HIV)/AIDS pandemic. With the purpose of designing new chemical entities with enhanced antiretroviral potencies, the Quantitative Structure–Activity Relationships (QSAR) study carried out on 122 novel piperidin‐4‐carboxamide derivatives as antagonists of HIV Chemokine Receptor 5 (CCR5) coreceptor binding is presented. The developed model was validated by standard QSAR parameters and through a detailed structural investigation on how it explains and reproduces the quantitative differences observed in the experimentally known activity data. The model showed a good correlative and predictive ability having a cross‐validated correlation coefficient (r2cv) of 0.794 and the conventional correlation coefficient (r2) was found to be 0.830. The study revealed that the CCR5 antagonistic activity exhibited by the series is largely explained by lipophilicity and steric bulkiness of substituents and that substituents with higher lipophilicity and steric superiority are required to make favorable antagonist–CCR5 interaction chemistry. A detailed investigation was made on the structural basis for the antiretroviral activity and the insights gleaned from the study could be usefully employed to design antagonists with a much more enhanced potency and selectivity.
Technical new feature
Authors: Kozempel M. F. , Stabile R. L. , Craig J. C. , Sinnamon H. I. , Aceto N. C. 
Published: May 2008

AbstractA continuous process for the commercial production of isopropenyl stearate (IPS) from triple pressed stearic acid and a stabilized form of propyne has been developed. Cost estimates, including capital costs, operating costs, and profitability, for commercial scale plant production which show the process to be economically feasible are presented. This potentially profitable process offers the advantages of reliable raw material sources, minimal external thermal requirements, and usable process waste streams. For a plant producing 5 million pounds of IPS per year, the selling price range is 80 to 107 cents/lb IPS, corresponding to a raw material cost range of 27 to 54 cents/lb of IPS. For a 20 million pound per year plant, the selling price range is 58 to 85 cents/lb IPS. The selling prices include a 20% annual return on fixed capital investment. Fixed capital requirement ranges from 2.7 to 10.9 million dollars (3rd quarter, 1975) for plants ranging in size from 5 to 50 million pounds of IPS per year, respectively.
Direct analysis of trivernolin by high‐performance liquid chromatography
Authors: Plattner R. D. , Wade K. , Kleiman R. 
Published: May 2008

AbstractA rapid liquid chromatographic method for the quantitation of trivernolin in epoxy seed oils has been developed. A weighed sample of the oil is dissolved in chloroform (∼100–300 mg/ml), and a 1–20µl portion of the oil is chromatographed on a 2 ft×1/4 in. OD C18µ‐Bondapak column with acetonitrile‐acetone (2:1, v/v). The area of the trivernolin peak from the differential refractometer recorder tracing is converted toµg trivernolin by use of a calibration curve of peak area vs. trivernolin weight.
Factors affecting product specificity of peanut lipoxygenase
Authors: Singleton J. A. , Pattee H. E. , Nelson M. S. 
Published: May 2008

AbstractProduct specificity of peanut lipoxygenase with linoleic acid as the substrate was determined under different conditions. Extraction solvent, extraction temperature, and reaction temperature only slightly affected the isomeric hydroperoxide ratio. A more pronounced effect was reflected in the total amount of hydroperoxide produced and extracted. CHCℓ3:CH3OH was the most thorough solvent, and extraction temperature of 25 C increased the total amount of hydroperoxides recovered. Lower reaction temperatures produced greater quantities of total hydroperoxides. Oxygen tension and pH value markedly affected changes in the hydroperoxide isomeric ratio and the total amount of hydroperoxides produced. Isomerization of the isolated hydroperoxides occurred very rapidly at 25 C, and a linear isomerization rate was observed at 4 C. At −20 C isolated hydroperoxides isomerized only slightly. Concentration of isolated hydroperoxides affected isomerization of the isomeric hydroperoxides; storing hydroperoxides in dilute solutions was most effective in preventing isomerization.
A solvent‐free synthesis of sucrose polyesters
Authors: Rizzi George P. , Taylor Harry M. 
Published: May 2008

AbstractA solvent‐free reaction system is described for making sucrose polyesters (SPE) by interesterification of sucrose and long chain fatty acid methyl esters. The process avoids the usual toxic solvents by using a novel two‐stage reaction sequence. In the first stage a 3:1 mole ratio of methyl esters to sucrose is reacted in the presence of potassium soaps to form a one phase melt containing mainly lower esters of sucrose. In the second stage more methyl esters are added and reacted to produce SPE in yields up to 90% based on sucrose. Sucrate ion generated in situ with alkali metal hydrides or Na‐K alloy proved to be a superior catalyst for formation of sucrose esters during both stages.
Use of carrier‐bound lipid substrates in enzymatic work
Authors: Tiru Mandayam , Tiru Maj‐Britt , Juhlin Rolf 
Published: May 2008

AbstractA procedure has been developed for the adsorption of oily or solid substrates of low water solubility onto inert carriers having large specific surface areas. This technique improves the handling characteristics of such substrates, enhances the standardization of enzymes, and facilitates separation of a carrier‐bound substrate/product from the reaction mixture.
Energy and moment of the Earth’s rotation elastic field
Authors: Vikulin A.V. 
Published: May 2008

Abstract
The problem of an elastic stress field in a rotating medium is formulated and solved analytically within the limits of the classical theory of elasticity with a symmetrical stress tensor. This is a rotation elastic field of action at a distance. There are two specific types of elastic waves with a moment in rotating media: solitons and excitons, or rotation waves. The soliton solutions to the wave equation represent waves of global earthquake migration (slow tectonic waves) which are no faster than ∼1 cm/s, i.e., approach the migration velocity of large and great earthquakes (M &gt; 7.5). The exciton solutions correspond to waves of local migration of foreshocks and aftershocks in earthquake sources (fast tectonic waves) and have their maximum velocity comparable to faulting rate and/or to S-wave velocities.
The role of landscape in insect ecology and its implications for agriculture.
Authors: Hunter M. D. 
Published: May 2008

Abstract
Landscape ecology is the study of spatial context and can greatly inform the management of insects within agricultural systems. During the last 5 years, considerable progress has been made in understanding the role of landscape structure in the population ecology of pests, the efficacy of natural enemies, the performance of pollinators and the biological diversity of agricultural communities. Processes are now commonly examined at multiple hierarchical spatial scales, and the behaviour of organisms is considered key to understanding species distributions. An increasing number of studies demonstrate that patch size and isolation are only two of the many interacting factors that determine the distribution of predators and prey on agricultural landscapes. The roles of contingency and system complexity are being considered in much more detail and are bringing increasing maturity to the field. Managing the quality of the matrix that lies between patches of habitat is receiving overdue attention, stemming from the recognition that habitat fragmentation is here to stay. Facilitating persistence within, and movement across, matrix habitat by a diversity of organisms is seen as key to agroecosystem health. Pollinator abundance and diversity remain causes for concern in many parts of the world. Habitat quality appears to be at least as important as patch size and isolation for many pollinators, and may be amenable to management within agricultural systems. Yet, there remain clear gaps in our understanding of the effects of landscape structure on insect abundance and diversity. The potential for evolutionary change in fragmented landscapes, the rates of recovery of arthropod communities after release from intensive land use and the contribution of landscape structure to disease dynamics are just a few of the areas that would benefit from significant research investment.
An elementary proof of the law of quadratic reciprocity over function fields
Authors: Ji Chun-Gang , Xue Yan 
Published: May 2008

Let

P
P

and

Q
Q

be relatively prime monic irreducible polynomials in

F

q

[
T
]

\mathbb {F}_{q}[T]

(

2
∤
q

2\nmid q

). In this paper, we give an elementary proof for the following law of quadratic reciprocity in

F

q

[
T
]

\mathbb {F}_{q}[T]

:

(

Q
P

)

(

P
Q

)

=
(
−
1

)

|

P

|

−
1

2

|

Q

|

−
1

2

,

\begin{equation*}\left (\frac {Q}{P}\right )\left (\frac {P}{Q}\right )=(-1)^{\frac {|P|-1}{2}\frac {|Q| -1}{2} },\end{equation*}

where

(

Q
P

)

\left (\frac {Q}{P}\right )

is the Legendre symbol.