bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of poly (p‐methylstyrene) ‐ graft‐poly (oxyethylene) and application as a polymeric surfactant in emulsion polymerization
Authors: Piirma Irja , Lenzotti James R. 
Published: April 2007

AbstractPoly(p‐methylstyrene)‐graft‐poly(oxyethylene) copolymers were prepared from p‐methylstyrene and æ‐hydroxy‐ω‐methyl‐poly(oxyethylene) using a ‘grafting on to’ technique. A total of 10 copolymers were synthesized varying in the hydrophobic back bone chain lengths, hydrophilic branch lengths and frequency of branches. The stabilizing efficiency of these amphipathic copolymers was studied in the emulsion polymerization of styrene. Using the number, size and size distribution of the particles as the criterion of stability, it was found that the polyoxyethylene (PEO) chain length is not as crucial for stability as the availability of the backbone for anchoring. A change in the backbone chain length (from M̄n = 1000 to 24000) with the same percent PEO had no effect on the outcome of the reaction: the latices stabilized to the same number of particles of the same size.
Polymerization of N‐vinylcarbazole initiated by UV‐radiation
Authors: Usanmaz Ali , Onal Ahmet M. , Bostan Serap 
Published: April 2007

AbstractThe solid‐state polymerization of N‐vinylcarbazole initiated by UV‐radiation at 25, 32.5, and 45°C was studied. The rate of polymerization increased with increase in temperature. The limiting conversion at all temperatures is 56%. The molecular weight, determined by viscosity measurements, first increased, reached a maximum, then decreased. The molecular weight distribution, studied by GPC, was broad with a shoulder on the low molecular weight side. The morphology of partially polymerized single crystals was studied by electron scanning microscopy to determine the propagation mode of polymerization with respect to the monomer structure. The high activation energy of 71‐9kJ/mol and ESR spectrum suggest a radical mechanism of polymerization.
Formation of polymer‐polymer complexes and blends in the system poly(acrylic acid)‐poly(vinyl methyl ether)
Authors: Cowie John M. G. , Garay M. Teresa , Lath Dieter , McEwen Lain J. 
Published: April 2007

AbstractThe formation of a 1:1 polymer‐polymer complex from poly(acrylic acid) and poly(vinyl methyl ether) has been detected by viscosity measurements in aqueous solution, and the glass transition temperature of the isolated complex has been determined. Infrared spectroscopy indicates that specific hydrogen bonding occurs between the components of the complex. Miscible blends of the two polymers can also be formed (at all compositions) and, although hydrogen bonding occurs, the structures of the blends are likely to be dissimilar to that of the complex.
Reactive microgels—polymers intermediate in size between single molecules and particles
Authors: Funke Werner 
Published: April 2007

AbstractReactive microgels are considered as soluble intramolecular cross‐linked macromolecules, with sizes comparable to linear or branched macromolecules and reactive groups at their surface or interior. This article is the written version of a Macrolux 1988 lecture. It presents the history and some more important results and relationship of synthesis, characterization and properties of this group of polymers and refers briefly to application.
Surface analyses of corona‐treated poly(ethylene terephthalate)
Authors: De Puydt Yves , Bertrand Patrick , Novis Yvan , Caudano Roland , Feyder Gusty , Lutgen Pierre 
Published: April 2007

AbstractPoly(ethylene terephthalate) (PET) Mylar® samples were treated by corona discharge in order to improve their adhesive properties. The corona treatments were performed in different atmospheres including nitrogen, ammonia and air.X‐ray photoelectron spectroscopy (XPS) was used to investigate the chemical modifications induced at the PET surface by these corona treatments. XPS results show that nitrogen incorporation takes place in the form of non‐oxygenated nitrogen functionalities, like amine or cyano groups. These are present at the surface of all the corona‐treated samples but in different concentrations depending on the gases used in the corona discharge. Furthermore, XPS analyses performed after heating of the treated samples show a higher thermal stability of the corona‐induced surface modifications in the case of nitrogen and ammonia.Ion scattering spectroscopy (ISS) and static secondary ion mass spectroscopy (SIMS) analyses were also performed because of their higher surface sensitivity compared with XPS: ISS reveals that nitrogen is not present at the topmost surface layer of the treated samples but is incorporated just beneath. The outermost surface layer presents a composition rich in oxygen. Finally, static SIMS spectra show that corona treatment induces more surface degradation when performed in air compared with nitrogen or ammonia.These results are discussed in relation to adhesive properties of PET.
Thermal stability of some heat‐resistant elastomers
Authors: Knight G. J. , Wright W. W. 
Published: April 2007

AbstractThe thermal stabilities of four fluoroelastomers, a polyphosphazene elastomer and four polysiloxanes, mainly in the vulcanised state, have been compared by isothermal weight loss experiments in nitrogen, or in air. The overall activation energies for degradation as a function of percentage conversion to volatiles have also been determined. In the majority of cases there was a linear relationship between activation energy and percentage conversion but the slope may be positive, negative or zero.
Dislocation‐induced deep levels in ELO InP revealed by point contact photocapacitance measurements
Authors: Oyama Yutaka , Kimura Toshihiro , Nishizawa Jun‐ichi 
Published: April 2007

Abstract30K‐photocapacitance and excitation photocapacitance methods were applied to reveal the dislocation‐induced deep levels in coalescent epitaxial lateral overgrowth layers of InP. Point‐contact Schottky barrier junctions with small junction areas were formed on dislocated and dislocation‐free regions. In the dislocation‐free layers, the dominant deep level was located at Ec‐1.30 eV, whereas in the dislocated area, dominant deep levels were detected at Ec‐0.86 eV and 1.05 eV. A neutralized state was also detected at 0.66 eV+Ev. Excitation photocapacitance results have shown that the defect configuration coordinate diagram of the dislocation‐induced deep levels was considered with large Frank‐Condon shifts of 0.28 eV. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
220 GHz low‐noise amplifier MMICs and modules based on a high performance 50 nm metamorphic HEMT technology
Authors: Tessmann A. , Leuther A. , Massler H. , Riessle M. , Kuri M. , Zink M. , Reinert W. 
Published: April 2007

AbstractA metamorphic composite‐channel InAlAs/InGaAs based high electron mobility transistor (MHEMT) technology has been developed for active and passive high‐resolution imaging applications. The technology features 50 nm gate length in combination with an In content of 80% in the main channel and 53% in the second channel. An extrinsic transit frequency ft of 400 GHz and an extrinsic maximum transconductance gm,max of 1800 mS/mm were measured at a drain voltage of 1 V. Based on this advanced MHEMT technology, coplanar G‐band low‐noise amplifier (LNA) MMICs were realized, achieving a small‐signal gain of more than 15 dB between 192 and 230 GHz together with an average noise figure of 8 dB. Furthermore, mounting and packaging of the monolithic amplifier chips into G‐band waveguide modules was accomplished with only minor reduction in circuit performance. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐dimensional simulation of GaInP/GaAs/Ge triple junction solar cell
Authors: Li Z. Q. , Xiao Y. G. , Li Z. M. Simon 
Published: April 2007

AbstractIn this work, two‐dimensional simulation has been performed on the triple‐junction (TJ) GaInP/GaAs/Ge solar cell devices based on the Crosslight APSYS with improved tunnel junction model. The APSYS simulator solves several interwoven equations including the basic Poisson's equation, and drift‐diffusion current equations for electrons and holes. Basic physical quantities like band diagrams, optical absorption and generation are calculated. The simulated IV characteristics and offset voltage agree well with the published experimental results for TJ GaInP/GaAs/Ge solar cell device. The quantum efficiency spectra have also been computed. Possible design optimization issues to enhance the quantum efficiency have also been discussed with respect to some applicable features of Crosslight APSYS. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light extraction study of LED using ray tracing computer simulation
Authors: Shmatov Oleksiy 
Published: April 2007

AbstractThis paper presents optical simulation results of different types of compound semiconductor LEDs. Transmitted light power angular distribution and other important LED properties have been studied in order to define how exactly geometry, contacts, layers, coating or encapsulating can change major LED parameters in complex. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
2D‐patterned ferromagnetic III‐Mn‐V semiconductors for planar spintronics
Authors: Farshchi R. , Chopdekar R. V. , Suzuki Y. , Ashby P. D. , Sharp I. D. , Beeman J. W. , Haller E. E. , Dubon O. D. 
Published: April 2007

AbstractWe demonstrate planar patterning techniques to produce isolated regions of ferromagnetic Ga1–xMnxAs embedded in a GaAs host. One technique consists of ion‐implantation through lithographically defined resist, followed by pulsed‐laser melting. Planar Hall‐bar structures of Ga1–xMnxAs formed by this process show a large anomalous Hall signal along with negative magnetoresistance associated with the well‐known hole‐mediated ferromagnetic phase. In another technique patterning is achieved by selective hydrogenation of Ga1–xMnxAs, rendering exposed regions electrically insulating and magnetically inactive. The planar nature of these Hall‐bars allows for tuning the ferromagnetism by the integration of lateral gates to modulate the exchange‐mediating hole population in the Ga1–xMnxAs region, hence creating junction‐FET functionality. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Valence band anticrossing in mismatched III‐V semiconductor alloys
Authors: Alberi K. , Wu J. , Walukiewicz W. , Yu K. M. , Dubon O. D. , Watkins S. P. , Wang C. X. , Liu X. , Cho Y.‐J. , Furdyna J. K. 
Published: April 2007

AbstractThe valence band anticrossing model (VBAC) is applied to explain the composition‐dependent trends in dilute GaSbxAs1–x and GaBixAs1–x alloys. Photomodulated reflectance spectroscopy (PR) of GaSbxAs1–x shows a reduction of the fundamental bandgap energy as well as an increase of the spin‐orbit splitting energy with increasing x. The VBAC model predicts that these shifts are the result of a hybridization of the extended valence band states of GaAs with the localized states of the impurity atoms, which induce an upward movement of the valence band edge. Extrapolation of the model to other III‐(Sb,Bi)‐V alloys is also discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intrinsic irreversibility in semiconductor light emission
Authors: Ding D. , Johnson S. R. , Wang J.‐B. , Yu S.‐Q. , Zhang Y.‐H. 
Published: April 2007

AbstractThe study of the light emission in semiconductors using energy and entropy balance equations reveals that there is an intrinsic entropy generation built into the emission process. Such an irreversible property provides insight into the conversion of electrical energy into light. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab initio and DFT study of La3+ hydration
Authors: Buzko Vladimir , Sukhno Igor , Buzko Margarita 
Published: April 2007

AbstractAn ab initio study of the molecular geometry and stability of La(H2O) (n = 8–9) clusters at the restricted Hartree–Fock and second‐order Møller–Plesset levels is reported. The results obtained indicate that in aqueous solutions, the La3+ ion is primarily 9‐coordinate. The most popular DFT functionals were tested to calculated the dimensions of the La(H2O) aqua ion. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Applying the concept of patterns to systems architecture
Authors: Cloutier Robert J. , Verma Dinesh 
Published: April 2007

AbstractWhile much has been written about patterns in software engineering, little has been written about their application to systems architecting. This paper provides a discussion of patterns and their potential applicability to complex system architecting. A historical introduction to the concept of patterns is provided along with their evolution from the domain of civil architecture to other engineering disciplines and domains. The relevance and applicability of patterns to systems architecting is then examined. Research with regard to developing a pattern form for documenting patterns for systems architecting is presented, and this is demonstrated on a command and control pattern, using both IDEF0 and UML. The application of this pattern within a functional architecture is then explored. Finally, recommendations for the development and management of a systems architecting and architecting pattern repository are offered. © 2007 Wiley Periodiocals, Inc. Syst Eng 10: 138– 154, 2007
Design of virtual plant environment for future generation green production systems
Authors: Gabbar Hossam A. 
Published: April 2007

AbstractThe operator is a key player in plant operation. However, his tasks and role became more complex with increasing safety and environmental challenges. Plant operation is no longer limited to production lines, but it also includes water, recycle, energy, and other processes that have been integrated with the production process to ensure green production systems. This research work proposes a new operation framework by introducing a design of a virtual plant that can support the operation of future green production systems. Operator activities are modeled in view of production, water treatment, waste, and energy generation processes. Human factors and data element visualization mechanisms are proposed to ensure smooth interaction for green production systems. © 2007 Wiley Periodicals, Inc. Syst Eng 10: 155–166, 2007
An overview of active and hybrid structural control research in the U.S.
Authors: Soong T. T. , Reinhorn A. M. 
Published: April 2007

AbstractUnder the leadership of the U.S. National Science Foundation in forming the U.S. Panel on Structural Control Research and in launching a program initiative in the area of structural control, there has been a surge of interest in this research field. Recent progress in active and hybrid control research in the U.S. is summarized in this paper. Some areas of research needs are identified and possible future directions for research and development in active and hybrid control are commented upon.
Seismic response of shallow‐floor buildings
Authors: Chow Hoong‐Leong , Selna Lawrence G. 
Published: April 2007

AbstractA framing system considered for a shallow‐floor building to be used in seismic zones has wide shallow beams with sufficient stirrups. Two‐way slab design is used for this system. This shallow‐floor system is likely to have good ductile behavior as the beams deform inelastically. The lateral resisting system is designed with a ‘strong column—weak beam’ ductile frame configuration so that the hinging zones occur within the beams away from the face of the column. The beams will be substantially wider than the columns. The joint and hinge regions must have sufficient tie and stirrup reinforcement. P‐delta effects should be considered but are not serious when drifts are controlled. The survivability of the ductile shallow‐floor building under moderate earthquakes is studied. The serviceability, e.g., story drift, of the building is of concern. The usual case is that the building is likely to satisfy code requirements for base shear resistance and corresponding story drift limitation. Contrary to code prediction, the performance under a moderate earthquake often yields large story drifts which may severely damage the non‐structural systems.
Drift control in moment resisting steel frame structures
Authors: Fuyama Hiroyuki , Krawinkler Helmut , Law Kincho H. 
Published: April 2007

AbstractThis paper presents the development of a design methodology for the control of interstory drift caused by equivalent static earthquake loads in tall moment resisting steel frame structures. The methodology captures the flexural and shear drift modes through approximate behavior‐based equations and attempts to minimize the total weight of the structural system with due consideration given to both strength and stiffness requirements. The methodology presented is part of an effort to develop a computer‐based design support system for the conceptual design of steel frame structures. This design support system, ‘Building Engineering and Reasoning Tool’ (BERT), together with the application of the drift control methodology, are discussed in a companion paper.
Analysis and seismic strengthening of concrete structures
Authors: Elhassan Rami M. , Hart Gary C. 
Published: April 2007

AbstractThe use of fiberglass/epoxy column jackets and passive energy dissipation systems as alternative methods for the reduction of the seismic hazard of concrete buildings is discussed. The use of the fiberglass/epoxy column jackets has the effect of increasing the shear capacity and the lateral displacement and flexural ductility of columns. The use of passive energy dissipation systems has the effect of reducing the force and deformation demands on buildings by dissipating the earthquake induced energy. These new concepts and technologies are presented through the seismic retrofit of two buildings: a seven‐story hotel and an eight‐story school building located in the city of Los Angeles.
Supplementary energy dissipators for maximum earthquake protection of tall building structures
Authors: Romero Enrique Martinez 
Published: April 2007

AbstractDuctility, or deformation energy, is by far the largest source of energy dissipation of structures, since normal levels of internal damping represent only a small portion of energy dissipation. However, large material deformations such as those required in building components to perform in a ductile manner, are often associated with cracking and degradation of its strength, particularly in concrete structures. The installation of some manufactured devices to critical regions of structural systems, specifically engineered to concentrate on them the largest part of the dissipated energy during an earthquake, increases the structure's overall thoroughness and improves its performance and reliability during major seismic events.Passive dissipation of energy is a promising trend in upgrading and retrofitting existing structures, since codes very seldom deal with detailed procedures to attain safe retrofits, as they strongly depend on the actual condition of the particular structure in each case. It is also sought as a very convenient method to reduce the impact of seismic forces on new structures, especially on tall and medium rise buildings in seismic regions.It is intended that the energy dissipative devices installed in the structure serve as a first defense line against seismic forces, leaving the structure itself and its inelastic reserve of strength, as a second defense line. If structures are designed in accordance to these criteria, the structures only receive part of the seismic forces calculated according to the Code, while the rest is being dissipated through the hysteric ductile behavior of the devices.Importantly, the hysteric cycles of steel plate devices, ADAS (Added Damping And Stiffness) provide substantial amounts of supplemental energy dissipation and internal damping to the structure, which can reduce the spectral acceleration and therefore, the earthquake forces.The 1987 Mexico Building Code1 contains no specific provisions regarding the use of energy dissipative devices of any type, and although it does not specifically admit their use, it does not forbid it either.In order to adopt this novel technique, the professional practitioner has to rely on analytical procedures not required by the Code to find what he believes to be the most appropriate procedure to a rational solution to the problem. It is necessary to identify the objective levels of system strength, stiffness and ductility, and be consistent with the selection of the input design earthquake.Being aware that system ductility is subjectively developed, and its basis comes largely from engineering judgment and intuition, the author encourages to look for a different seismic resistant approach in order not to depend only on ductility to resist earthquake peak demands
Simulation of input motions in wide period range for earthquake resistant design of super‐high‐rise buildings
Authors: Watabe Makoto , Dan Kazuo , Mita Akira , Ishii Toru 
Published: April 2007

AbstractA detailed dynamic analysis is performed that incorporates the response from eight possible earthquakes. These earthquakes are for the Tokyo metropolitan area. The building under study is a 550 meter super‐high‐rise building. The fundamental horizontal period of vibration is approximately 6 seconds and the damping is near 2 per cent.
New structural systems for tall buildings: The space‐truss concept
Authors: Pouangare C. C. , Connor J. J. 
Published: April 2007

AbstractThe dominant structural system used for buildings over 40 stories has been the framed tube and its modifications. Recently, new concepts have emerged leading to the development of space‐truss systems, which are more efficient and more economical than tubes. A few buildings have already been built on the space‐truss idea. In this paper, various structural concepts for tall and super‐tall buildings are proposed, and one of them is examined in detail. The issue of material selection is also addressed through a design approach based on material behavior under specific loading conditions and on the cost of the material. In addition, the generic design of a one‐hundred‐and‐twelve story building is presented as an application of the concept.
Confronting the Soviet Management Structure: Bureaucratic, But Workable
Authors: Kvint Vladimir L. 
Published: April 2007

AbstractBefore an MNC even begins negotiation to set up a joint venture in the Soviet Union or otherwise do business there, it needs to understand the labyrinthine Soviet management system it will encounter. Here, Vladimir L. Kvint, a prominent Soviet professor and business authority now heading up his own consulting business in New York City, offers insights into the Soviet management system.