bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal and mechanical properties of melt processed intercalated poly(methyl methacrylate)–organoclay nanocomposites over a wide range of filler loading
Authors: Tiwari Rajkiran R , Natarajan Upendra 
Published: December 2007

AbstractBACKGROUND: Poly(methyl methacrylate) (PMMA)–organoclay nanocomposites with octadecylammonium ion‐modified montmorillonite, prepared via melt processing, over a wide range of filler loading (2–16 wt%) were investigated in detail. These hybrids were characterized for their dispersion structure, and thermal and mechanical properties, such as tensile modulus (E), break stress (σbrk), percent break strain (εbrk) and ductility (J), using wide‐angle X‐ray diffraction, transmission electron microscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile and impact tests.RESULTS: Intercalated nanocomposites were formed even in the presence of 16 wt% clay (high loading) in PMMA matrix. PMMA intercalated into the galleries of the organically modified clay, with a change in d‐spacing in the range 11–16 Å. TGA results showed improved thermal stability of the nanocomposites. The glass transition temperature (Tg) of the nanocomposites, from DSC measurements, was 2–3 °C higher than that of PMMA. The ultimate tensile strength and impact strength decreased with increasing clay fraction. Tensile modulus for the nanocomposites increased by a significant amount (113%) at the highest level of clay fraction (16 wt%) studied.CONCLUSION: We show for the first time the formation of intercalated PMMA nanocomposites with alkylammonium‐modified clays at high clay loadings (>15 wt%). Tensile modulus increases linearly with clay fraction, and the enhancement in modulus is significant. A linear correlation between tensile strength and strain‐at‐break is shown. Thermal properties are not affected appreciably. Organoclay can be dispersed well even at high clay fractions to form nanocomposites with superior bulk properties of practical interest. Copyright © 2007 Society of Chemical Industry
Glyphosate‐resistant crops: adoption, use and future considerations
Authors: Dill Gerald M , CaJacob Claire A , Padgette Stephen R 
Published: December 2007

AbstractBACKGROUND: Glyphosate‐resistant crops (GRCs) were first introduced in the United States in soybeans in 1996. Adoption has been very rapid in soybeans and cotton since introduction and has grown significantly in maize in recent years. GRCs have grown to over 74 million hectares in five crop species in 13 countries. The intent of this paper is to update the hectares planted and the use patterns of GRC globally, and to discuss briefly future applications and uses of the technology.RESULTS: The largest land areas of GRCs are occupied by soybean (54.2 million ha), maize (13.2 million ha), cotton (5.1 million ha), canola (2.3 million ha) and alfalfa (0.1 million ha). Currently, the USA, Argentina, Brazil and Canada have the largest plantings of GRCs. Herbicide use patterns would indicate that over 50% of glyphosate‐resistant (GR) maize hectares and 70% of GR cotton hectares receive alternative mode‐of‐action treatments, while approximately 25% of GR soybeans receive such a treatment in the USA. Alternative herbicide use is likely driven by both agronomic need and herbicide resistance limitations in certain GR crops such as current GR cotton. Tillage practices in the USA indicate that > 65% of GR maize hectares, 70% of GR cotton hectares and 50% of GR soybean hectares received some tillage in the production system. Tillage was likely used for multiple purposes ranging from seed‐bed preparation to weed management.CONCLUSION: GRCs represent one of the more rapidly adopted weed management technologies in recent history. Current use patterns would indicate that GRCs will likely continue to be a popular weed management choice that may also include the use of other herbicides to complement glyphosate. Stacking with other biotechnology traits will also give farmers the benefits and convenience of multiple pest control and quality trait technologies within a single seed. Copyright © 2007 Society of Chemical Industry
A risk calculator for glyphosate resistance in Lolium rigidum (Gaud.)
Authors: Stanton Rex A , Pratley James E , Hudson David , Dill Gerald M 
Published: December 2007

AbstractBACKGROUND: Glyphosate resistance has been confirmed in 58 populations of Lolium rigidum (Gaud.), a major weed of crops in southern Australia. Extensive use of glyphosate in conjunction with minimal soil disturbance has been identified as high risk for resistance to that herbicide. Land managers need a simple method for rapid assessment of the risk of resistance occurring as a result of past and proposed future management practices. Modelled on risk assessment nomographs, a simple calculator for indicating the risk of evolved glyphosate resistance in L. rigidum is described.RESULTS: The calculator uses the generations since first use and the frequency of use of glyphosate in combination with historical cultivation levels as critical factors for determining the risk of glyphosate resistance evolution. Based on the management history of a field, a land manager can graphically determine a glyphosate resistance risk for that field.CONCLUSION: The calculator enables the farmer or the advisor to assess the risk of a weed's population becoming resistant and modify practices accordingly to manage for sustainable glyphosate use. The risk calculator could be modified for other herbicides and different weed species. Copyright © 2007 Society of Chemical Industry
Comparison of herbicide regimes and the associated potential environmental effects of glyphosate‐resistant crops versus what they replace in Europe
Authors: Kleter Gijs A , Harris Caroline , Stephenson Gerry , Unsworth John 
Published: December 2007

AbstractWhile cultivation of transgenic crops takes place in seven of the EU member states, this constitutes a relatively limited part of the total acreage planted to these crops worldwide. The only glyphosate‐resistant (GR) crop grown commercially until recently has been soybean in Romania. In addition, large‐scale experimental European data exist for GR sugar and fodder beets, and, to a lesser extent, GR oilseed rape. These GR crops are likely to have an impact both on the use of herbicides and on the environmental impact of the latter. From the data on these GR crops, it appears that quantities of herbicides applied to GR beets are decreased while those on GR soybean are slightly increased compared with their conventional counterparts. Depending on the parameters used for prediction or measurement of environmental impacts of GR crops, generally similar or less negative impacts were observed compared with conventional crops. Favourable environmental effects of the glyphosate‐containing herbicide regimes on GR crops appear feasible, provided appropriate measures for maintaining biodiversity and prevention of volunteers and gene flow are applied. Copyright © 2007 Society of Chemical Industry
Magnetocaloric effect in as‐quenched and annealed Fe91–xYxZr9 (x = 0.5, 10) alloys
Authors: Kim K. S. , Kim Y. S. , Zidanic J. , Min S. G. , Yu S. C. 
Published: December 2007

AbstractThe magnetization behaviours have been analyzed for as‐quenched and annealed Fe91–xYxZr9 (x = 0, 5, 10) alloys. Samples were prepared by arc melting the high‐purity elemental constituents under argon gas atmosphere and by single roller melt spinning. These alloys were annealed one hour at 500 °C. The magnetic properties of the samples were measured by VSM. The Curie temperature increases with increasing Y concentration (x = 0 to 10). Temperature dependence of the entropy variation ΔSM was found to appear in the vicinity of the Curie temperature. The results show that annealed Fe86Y5Zr9 alloys have a greater magnetocaloric effect than that those in as‐quenched alloys. The value is ‐1.23 J/kg K at ΔH = 1.5 T for annealed alloy and ‐0.89 for as‐quenched alloy, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of buffer layers on the texture and magnetic properties of Co/Pt multilayers with perpendicular anisotropy
Authors: Kanak J. , Czapkiewicz M. , Stobiecki T. , Kachel M. , Sveklo I. , Maziewski A. , van Dijken S. 
Published: December 2007

AbstractA study on the buffer layer dependence of film texture, surface roughness, and magnetization reversal mechanism in Co/Pt multilayers is presented. Four different buffers are used: (A) 10 nm Cu, (B) 5 nm Ta/10 nm Cu, (C) 5 nm Ta/10 nm Cu/5 nm Ta, and (D) 5 nm Ta/10 nm Cu/5 nm Ta/10 nm Cu. The growth of [2 nm Pt/0.5 nm Co]5/2 nm Pt on top of these buffer layers results in a large variation of film textures and surface morphologies. Samples with a Cu buffer (A) exhibit a low degree of film texture and are relatively rough. MOKE and MFM measurements on these films reveal that the magnetization reverses by the nucleation of numerous small domains due to a large dispersion of the activation energy barrier. Buffer layer structures where the first layer consists of Ta, on the other hand, result in (111)‐textured Co/Pt multilayers with a more regular surface morphology. In these samples, magnetization reversal proceeds by fast domain wall movement. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of the texture on properties of IrMn spin valve magnetic tunnel junctions with MgO barrier and CoFeB electrodes
Authors: Kanak J. , Stobiecki T. , Drewello V. , Schmalhorst J. , Reiss G. 
Published: December 2007

AbstractThe influence of seed‐buffer layers on the texture and tunneling parameters was investigated. The spin valve magnetic tunnel junctions (SV‐MTJs) were deposited onto thermally oxidized Si wafers by magnetron sputtering in the following sequence of layers: substrate Si(100)/SiO2 47 nm/buffer layers/ Ir17Mn83 10 nm/CoFeB 3 nm/MgO 2 nm/CoFeB 4 nm/top layers. The following buffer systems have been used in order to induce different degree of the texture: (A) low textured buffer Cu 25 nm and (B) high textured buffer Ta 5 nm/Cu 25 nm. The type of buffer layers strongly influences the texture of IrMn antiferromagnetic layer and induces roughness of magnetic layers and MgO barrier. The highest TMR ratio 141% was obtained for sample with small roughness annealed in vacuum at 350 °C. A strong influence of the roughness, due to the barrier thickness fluctuations, on the resistance‐area product (RA) of the junctions is discussed. The Néel coupling field increases in case of high textured and rough layers and it becomes small for smooth interfaces. The proper design of the composition of the buffer layers allows to improve the magnetic and tunneling properties of MTJs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Feasibility study of micro‐undulator for T‐ray sources by using FEM
Authors: Jang Pyungwoo , Rhie Keungwon , Lee Byungcheol 
Published: December 2007

AbstractPossibility of development of micro‐undulator utilizing perpendicular magnetic recording was explored by 2‐D FEM simulation. In the simulation FePt and CoCr layer were compared as an appropriate recording layer of the undulator. Also variation of maximum field and THD with aspect ratio and gap height were simulated so that they should be optimized in a given thickness of recording layer. From both the simulation results and Bitter patterns recorded on FePt/Fe micro‐undulator, the possibility of development of micro‐undulator by utilizing perpendicular recording technique could be confirmed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic switching instability of ultrathin magnetic films under crossing pulse fields with duration shorter than relaxation time
Authors: Han Yoonsung , Lee Sangho , Kim Sunghoon , Lee Jinwon , Kim Ahram , Hong Jongill 
Published: December 2007

AbstractWe have studied the magnetization switching behaviour of ultra‐thin films when we apply synchronous longitudinal and transverse pulse fields with duration shorter than relaxation time. The film was rectangular Permalloy with a dimension of 800 × 300 × 2 nm. In the case of a pulse duration of 100 ps, the switching map showed the c‐shaped switching characteristics rather than the typical quasi‐static asteroid. We found that the c‐shaped switching characteristics are associated with the abnormal switching behaviour. The abnormal switching area was also found for a pulse duration of 300 ps and even in the precessional switching region for a pulse duration of 500 ps. Our results show that the transient non‐uniform demagnetization developed by the crossing pulses is responsible for such abnormal switching behaviour, and this is supported by simulation for the elliptical film whose demagnetization field distribution is relatively uniform. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNA electrophoresis under the gradient magnetic field
Authors: Yoshida Kohei , Ozawa Shun , Yamamoto Isao , Yamaguchi Masuhiro , Ogawa Kyohei , Takamasu Tadashi 
Published: December 2007

AbstractThe magnetic field effects on DNA electrophoresis have been investigated under the gradient and the homogeneous magnetic fields. The electrophoretic distance of the DNA is different between them. The increase and decrease in the electrophoretic velocity are discovered in the gradient magnetic fields. The acceralation and decceralation of DNA are observed in the negative and positive gradients of the magnetic fields, respectively. The results are discussed with the magnetic force and a new separation method of DNAs is suggested. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrasoft magnetic properties of Co–Fe–Hf–O nanocomposite films
Authors: Ha N. D. , Phan M. H. , Tuan L. A. , Phan T. L. , Kim C. G. , Kim C. O. , Yu S. C. 
Published: December 2007

AbstractThis paper reports on the excellent high‐frequency magnetic performance of Co–Fe–Hf–O thin films, which were deposited on Si(100) substrates by the oxygen reactive rf‐sputtering method. It was shown that the films possessed not only high electrical resistivity but also large saturation magnetization and hard‐axis anisotropy field. Among the compositions investigated, Co19.35Fe53.28Hf7.92O19.35 exhibited the ultrasoft magnetic properties of high saturation magnetization, 4πMs ∼19.86 kG, and low coercivity, Hc ∼1.5 Oe. The magnetic permeability remained almost constant up to 3 GHz and reached a maximum at the ferromagnetic resonant frequency of 4.024 GHz. These properties of this film together with a high electrical resistivity of 3569 μΩcm make it ideal for producing micromagnetic devices for high‐frequency applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetocaloric manganites: Progress and challenges
Authors: Phan Manh‐Huong , Yu Seong‐Cho 
Published: December 2007

AbstractMagnetic refrigeration based on the magnetocaloric effect (MCE) becomes a topic of internationally current interest. This enabling technology provides several advantages (e.g. high energy efficiency, small volume, non‐pollution) over a conventional gas compression technique. It depends heavily upon the magnitude of MCE of magnetic substances that are used as working refrigerants. Therefore, current research is focused on a search for new materials that are low cost and exhibit small magnetic field‐induced large MCEs. This paper aims to review the recent developments of a new class of magnetocaloric material, namely, ferromagnetic manganites (R1‐xMxMnO3, where R = La, Nd, Pr and M = Ca, Sr, Ba, etc.). The good magnetocaloric properties of ferromagnetic manganites in addition to their flexibility and cost‐effectives make them very promising for active magnetic refrigeration (AMR) applications in the temperature range of 30–375 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Domain walls, domain wall transformations and structural changes in permalloy nanowires when subjected to current pulses
Authors: Hempe E.‐M. , Kläui M. , Kasama T. , Backes D. , Junginger F. , Krzyk S. , Heyderman L. J. , Dunin‐Borkowski R. , Rüdiger U. 
Published: December 2007

AbstractWe report the direct transmission electron microscopy observation of spin structure transformations in nanoscale Permalloy zigzag wires due to Joule heating during the injection of current pulses. This heating is sufficient to overcome the energy barriers separating the different metastable domain wall spin structures. Due to the large energy barriers these are stable and observable at room temperature by off‐axis electron holography and Fresnel imaging. The interaction between different domain walls is probed and the main pinning mechanism is determined to be the edge roughness. In addition to transformations, we also report on thermally assisted domain wall hopping between two pinning sites and structural changes that occur when the samples are subjected to even higher current pulses. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and magnetic properties of nano Ba‐hexaferrite/NiZn ferrite composites
Authors: Moon K. W. , Cho S. G. , Choa Y. H. , Kim K. H. , Kim J. 
Published: December 2007

AbstractBa‐hexaferrite and Ni0.5Zn0.5 ferrite nano composites have been successfully fabricated by a self‐propagating combustion method. Transmission electron microscopy and X‐ray diffractometer analysis showed that two ferrite phases were homogeneously distributed and the measured grain size of them around 20nm. The saturation magnetizations of the composites were revealed to be increased compared with the theoretical values. These increments of the saturation magnetization values could be explained by the exchange spring interaction between soft and hard magnetic phases. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of measurement geometry on permeability extracted by a broadband method
Authors: Cho S. G. , Kim J. , Kim I. , Kim K. H. , Yamaguchi M. 
Published: December 2007

AbstractA broadband coplanar waveguide method, recognized as a simple and effective broadband permeability measurement tool, was used to measure the frequency dependent permeability of various magnetic thin films. It was revealed that measured permeability was strongly dependent on the dimension of the films and the geometry of the waveguide. This dependency was proven to result from the confinement of magnetic fields in the films by LLG equation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of an electric field‐induced stress on the magnetic properties of amorphous Terfenol‐D films deposited on PMN‐PT single crystal substrates
Authors: Kim Ju‐Hyun , Ravindranath V. , Shin Sung‐Chul 
Published: December 2007

AbstractAmorphous Terfenol‐D films were deposited on piezoelectric PMN‐PT single crystal substrates in order to study the effect of an electric field‐induced stress on its magnetic properties. The stress was generated by a voltage applied across the PMN‐PT substrate by means of a bottom Au electrode and a Pt capping layer (top electrode) deposited on Terfenol‐D. Due to the inverse piezoelectric effect of the PMN‐PT substrate, the Terfenol‐D film is subjected to an isotropic planar stress. For a voltage variation from 0–90 V, an increase in the coercivity from 385 Oe to 444 Oe has been observed. This may be due to an increase in the compressive stress on the film, which is explained by a model describing the stress dependence of the domain wall pinning strength. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Different nanostructure cathode catalysts application for direct methanol fuel cell
Authors: Dipti Sharmin Sultana , Chung Uoo‐Chang , Kim Jong‐Pil , Chung Won‐Sub 
Published: December 2007

AbstractDirect methanol fuel cell (DMFC) belongs to the same family of energy conversion device and the application of new hydrogen storage nanomaterials such as carbon nanotube (CNTs) supported catalysts is being addressed in an increasing industrial approach. In this present study, multiwall carbon nanotube supported Pt and Pt‐Ni nanoparticles were prepared as cathode catalysts for direct methanol fuel cell application. Transmission electron microscopy and X‐ray diffraction analyses indicated the formation of well‐dispersed Pt and Pt‐Ni nanoparticles having sizes of around 2 ∼ 4 nm on carbon nanotube. Furthermore, the electrochemical characterization by the cyclic voltammetry (CV) demonstrated that these catalysts have higher catalytic activity and the methanol oxidation reaction of the Pt‐Ni/CNTs is respectively almost similar and slightly higher than Pt/CNTs electrocatalysts. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and microwave properties of highly permeable FeCo‐based nano‐alloys
Authors: Wu Jun Hua , Kim Young Keun 
Published: December 2007

AbstractWe synthesized Fe and Co‐based (Fe48Co41Si3B8) alloy nanopowders by a mechanochemical technique and investigated their structure, magnetic and electromagnetic properties. The nanopowders have a bcc (A2) phase and demonstrate high magnetization with low coercivity. The analysis reveals that their magnetization process may be described by a two‐phase model. The microwave measurements performed by the coaxial method over a broad band up to 18 GHz show that the nanocomposites comprising the nanopowders possess high, broadband magnetic permeability, promising applications in electromagnetic shielding and microwave absorption. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics of domain wall motion in CoFe films for GHz frequency application
Authors: Watanabe T. , Munakata M. , Ohkoshi M. 
Published: December 2007

AbstractDynamic magnetization process is studied in CoFe films for high frequency application by using a time‐resolved imaging technique. The domain wall resonance has been found at 130 kHz in a slit‐patterned Co35Fe65 film with high saturation magnetization. The domain wall mobility of 20 m/sOe was observed at the resonant frequency. The effective wall mass, the viscous damping constant, and the restoring force constant were evaluated in the Co35Fe65 film. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tendency of temperature on nano‐pillar for spin transfer torque memory
Authors: Ha Seung‐Seok , You Chun‐Yeol 
Published: December 2007

AbstractThis study perform numerical analysis for a Joule heated nano‐pillar system, which has a tunneling barrier, using the hot electrons' dissipation concept. The main focus was on the temperature dependence of the radius, thickness of the nano‐pillar and input power using the finite element method. The published experimental conditions were considered for the calculations. It was found that the peak temperature T (t =tp ) depends on the dimensions of the nano‐pillar and input power. Surprisingly, the increase in temperature was in the order of only 1 Kelvin. The reason for such a small increase in temperature is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of the thermal conductivity of substrate on the temperature of nanowire for current induced domain wall motion
Authors: Ha Seung‐Seok , You Chun‐Yeol 
Published: December 2007

AbstractWe investigate the Joule‐heated nanowire temperature for current induced domain wall motion with a finite thickness insulator layer. The dependence of the temperature on the thermal conductivities of substrates and insulator layers, and the insulator layer thickness are studied by employing finite element method. We find that the increment of the temperature is roughly proportion to the inverse of thermal conductivity of the substrate and insulator layer. Furthermore, the increment of the temperature rises with the insulator thickness, and then saturates for the thick enough insulator layers. The results of the numerical calculations can be explained reasonably with the analytic solution for the Joule‐heated nanowire temperature, even though it is valid only for the case without an insulator layer. Our results suggest appropriate guideline for the design of the experiments. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)