bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonnormality estimation in projection‐type system realization methods
Authors: Bazán F. S. V. 
Published: November 2008

AbstractUsing Henrici's departure from normality as a tool, we investigate the influence of nonnormality on the spectral sensitivity of system matrices of projection‐type system realization methods. Basically, we show that the system matrix of one of these methods is diagonally similar to the system matrix of the classical Kung's method and, we then conclude that the spectral sensitivity of all methods decreases significantly under conditions that are often met or easy to impose in practice. On the basis of these results, we conclude thatallprojection‐type realization methods have essentially the same spectral properties as Kung's method. Furthermore, a theoretical eigenvalue error bound is derived and illustrated by numerical simulations. Copyright © 2008 John Wiley & Sons, Ltd.
Foz2006 numerical linear algebra and optimization
Authors: Gonzaga Clovis Caesar , Yuan Jin Yun 
Published: November 2008

AbstractThe special issue contains five papers from Foz2006—Congress on Mathematics and its Applications, held in Foz do Iguaçu, Brazil, on 7–11 August 2006, chaired by Yuan Jin Yun. The papers address preconditioners for saddle point problems, iterative methods, new family of penalty functions for optimization and their applications. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and characterization of a new kind of immobilized Mn(salen) and catalytic epoxidation of styrene on the catalyst
Authors: Shen Hongsheng , Fu Xiangkai , Bao Hebin , Chen Junxian , Gong Biwei 
Published: November 2008

AbstractA linear polystyrene‐isopropenyl phosphonic acid (PS‐IPPA) copolymer was newly synthesized by free radical reaction in solution with isopropenyl phosphonic acid (IPPA) and styrene. Zirconium poly(styrene‐isopropenyl phosphonate)‐phosphate acid (ZPS‐IPPA) was also synthesized. The benzene rings of ZPS‐IPPA were hydroxylated and then further reacted with Mn(salen)Cl. Thus the heterogeneous catalyst, Mn(salen) axially immobilized onto ZPS‐IPPA was synthesized. These substances were characterized by IR spectra, X‐ray diffraction (XRD), SEM, TEM, NMR, thermogravimetric analysis, and AAS. The catalyst showed good activity to epoxidation of styrene, which is close to that of the corresponding homogeneous catalyst. Copyright © 2008 John Wiley & Sons, Ltd.
A review on ternary immiscible polymer blends: morphology and effective parameters
Authors: Shokoohi Shirin , Arefazar Ahmad 
Published: November 2008

AbstractIn this paper a review of studies on ternary polymer blends, reported in the period from 1980s to 2007, is presented. This review covers the investigations carried out on the formation of morphologies observed in ternary blends including separated disperse, core–shell and co‐continuous morphologies; and also the parameters affecting the type of morphology and its distribution state. Copyright © 2008 John Wiley & Sons, Ltd.
Influences of poly(lactic acid)‐grafted carbon nanotube on thermal, mechanical, and electrical properties of poly(lactic acid)
Authors: Yoon Jin Tae , Jeong Young Gyu , Lee Sang Cheol , Min Byung Gil 
Published: November 2008

AbstractPoly(lactic acid)‐grafted multiwalled carbon nanotubes (MWNT‐g‐PLA) were prepared by the direct melt‐polycondensation of L‐lactic acid with carboxylic acid‐functionalized MWNT (MWNT‐COOH) and then mixed with a commercially available neat PLA to prepare PLA/MWNT‐g‐PLA nanocomposites. Morphological, thermal, mechanical, and electrical characteristics of PLA/MWNT‐g‐PLA nanocomposites were investigated as a function of the MWNT content and compared with those of the neat PLA, PLA/MWNT, and PLA/MWNT‐COOH nanocomposites. It was identified from FE‐SEM images that PLA/MWNT‐g‐PLA nanocomposites exhibit good dispersion of MWNT‐g‐PLA in the PLA matrix, while PLA/MWNT and PLA/MWNT‐COOH nanocomposites display MWNT aggregates. As a result, initial moduli and tensile strengths of PLA/MWNT‐g‐PLA composites are much higher than those of neat PLA, PLA/MWNT, and PLA/MWNT‐COOH, which stems from the efficient reinforcing effect of MWNT‐g‐PLA in the PLA matrix. In addition, the crystallization rate of PLA/MWNT‐g‐PLA nanocomposites is faster than those of neat PLA, PLA/MWNT, and PLA/MWNT‐COOH, since MWNT‐g‐PLA dispersed in the PLA matrix serves efficiently as a nucleating agent. It is interesting that, unlike PLA/MWNT nanocomposites, surface resistivities of PLA/MWNT‐g‐PLA nanocomposites did not change noticeably depending on the MWNT content, demonstrating that MWNTs in PLA/MWNT‐g‐PLA are wrapped with the PLA chains of MWNT‐g‐PLA. Copyright © 2008 John Wiley & Sons, Ltd.
Investigation of high‐T luminescence processes in ZnO nanorods grown catalytically by vapor‐transport method
Authors: Gupta A. , Omari M. , Kouklin N. 
Published: November 2008

AbstractHigh‐T luminescence properties of ZnO nanorods/nanowires grown on c‐Si by a catalyst‐assisted vapor‐liquid‐solid (VLS) method have been studied spectroscopically at the T‐range of 123‐573 K. The performed T‐dependent photoluminescence (PL) measurements confirm the presence of strong ultra‐violet (UV) and visible emission associated with excitonic and donor‐acceptor pair recombinations, respectively. A red shift in the UV peak position was analyzed within the framework of a three‐parameter model, with the results suggesting a stronger role of phonons behind the band gap renormalization effect at high T. The ratio of excitonic to defect integral PL intensities was observed to increase exponentially with T which is attributed to a strong increase in the net ionization rate of deep‐defects at T exceeding ∼400 K. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chitosan tailor‐made films: the effects of additives on barrier and mechanical properties
Authors: Yoshida Cristiana M. P. , Oliveira Junior Enio Nazaré , Franco Telma Teixeira 
Published: November 2008

AbstractWith the aim of achieving ‘tailor‐made’ chitosan films, the effects of several variables on the properties of chitosan films were studied. These variables were chitosan concentration and molecular weight of thermally depolymerized chitosan, addition of lipids (palmitic acid, beeswax or carnauba wax) and plasticizer (glycerol). The water vapour transmission rate (WVTR) and mechanical properties of these films were measured. The innovative feature of this study is that it provides specific information to support the design of tailor‐made films. These can only be formulated when the effects of the important variables are well understood. It was found that WVTR was reduced by 57% in film made from chitosan that had been thermally treated for 7 h at 100°C (molecular mass 13.7 kDa), while in the emulsion films, the WVTR was increased by incorporation of palmitic acid, beeswax or carnauba wax incorporation. The mechanical properties (tensile strength and elongation at break) were improved when glycerol was used as plasticizer, resulting in more elastic films (increasing the elongation at break by 62%). Copyright © 2008 John Wiley & Sons, Ltd.
QSAR Modeling of HIV‐1 Protease Inhibition on Six‐ and Seven‐membered Cyclic Ureas
Authors: Takkis Kalev , Sild Sulev 
Published: November 2008

AbstractA Quantitative Structure–Activity Relationship (QSAR) analysis was carried out on a dataset of 135 six‐ and seven‐membered cyclic urea‐based Human Immunodeficiency Virus Type 1 (HIV‐1) protease inhibitors. Using a larger and more diverse dataset than previous studies reported in literature allowed a more comprehensive analysis. A large set of molecular descriptors, calculated with CODESSA PRO, was used in Multiple Linear Regression (MLR) analysis and the resulting four‐parameter model enabled accurate prediction of inhibitory activity for the structures both in training and external validation sets. The squared correlation coefficient for both sets combined is 0.824. Descriptors in the final model characterize the size and shape of the molecule and its charge distribution. Non‐linear relationships between the HIV‐1 protease inhibition activity and some descriptors are significant and described with simple non‐linear transformations. After the model development, another dataset of 45 compounds was collected and additional external validation was performed.
ONIOM study of the nonbonding interaction of the 2PU inhibitor with the CDK2 and CDK4 cyclin‐dependant kinases
Authors: Li Aixiao , Maurel François , Delamar Michel , Wang Baoshan 
Published: November 2008

AbstractWe discuss in this article, the applicability of hybrid techniques [especially the our‐own N‐layered integrated molecular orbital and molecular mechanics (ONIOM) method] to weak chemical interactions in large systems, such as the interaction of cyclin‐dependant kinases, CDK4, and CDK2, with a specific ligand (2PU) showing selectivity for CDK4. Our results show that the energies from the ONIOM calculations perfectly match our former molecular dynamics results, both for determining the amino acids which have strongest interactions with the ligand and for explaining the selectivity of 2PU towards CDK4, as compared with CDK2. We show that the ONIOM method is a good candidate for studying such interactions in large systems, even though there are still some technical and theoretical problems to solve. The calculation details will be presented together with the methodology we devised for using the ONIOM approach in such a context. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Stepwise inter‐frame correlation‐based steganalysis system for video streams
Authors: Liu Bin , Liu Fenlin , Yang Chunfang 
Published: November 2008

Abstractstage‐wise steganalysis system that utilizes the collusion scheme among sucessive video frames is proposed. The effect of local motion interfering detection precision is studied. The local motion and message embedded in video frame is treated as a bimodal noise. To detect the existence of the embedded message, blockwise correlation‐based feature extraction scheme is proposed to reduce the local motion interfering effect. The video steganalysis process is divided into two stages. In the first stage, suspicious video frames will be recognized by decision module employing features extracted with a light‐weight collusion scheme, for the real‐time requirement. In the second stage, suspicious frames will be analyzed critically by the present powerful image steganalysis algorithms. Moreover, the determined principle is also studied to reduce the false positive rate in the first stage. Experimental results show the satisfying performance of the proposed system. Copyright © 2008 John Wiley & Sons, Ltd.
Surface characterization of the SiOx films prepared by a remote atmospheric pressure plasma jet
Authors: Huang Chun , Liu Chi‐Hung , Wu Shin‐Yi 
Published: November 2008

AbstractThe deposition rate and surface properties of SiOx films were prepared and investigated using remote atmospheric pressure plasma (APP) jet. The APP, generated with low frequency power at 16 kHz, was fed with tetraethoxysilane (TEOS)/air gas mixture. After deposition, the SiOx films were analyzed for chemical characteristics, elemental composition, surface morphology, and hardness. It was found that the deposition substrate temperature is the key factor to affect the deposition rate of remote APP chemical vapor deposition process. Fourier transform infrared (FTIR) spectra indicated that APP deposited SiOx films are an inorganic feature. XPS examination revealed that the SiOx films contained approximately 30% silicon, 58% oxygen and 12% carbon. Atomic forced microscopy (AFM) analysis results indicated a smooth surface of SiOx films in deposition under higher substrate temperature. Also, pencil hardness tests indicated that the hardness of APP deposited SiOx films was greatly improved with increasing substrate temperatures. Copyright © 2008 John Wiley & Sons, Ltd.
Improved efficiency of the sputtering technique for pyrite surface and its effect on reduction of electron beam damage
Authors: Moslemzadeh N. , Tamara M. , Raval R. , Prior D. , Preston M. R. 
Published: November 2008

AbstractA quick and highly efficient method is described for the preparation of clean and well‐characterised (100) pyrite surfaces on natural crystals based on a sputter/annealing procedure in an ultra‐high vacuum (UHV) chamber. The improvement has been achieved by controlling the ingress of the key contaminants water and oxygen and restricting the annealing temperature to 560 K, which is below the SO2 dissociation temperature. Low‐energy electron diffraction (LEED) and X‐ray photoelectron spectroscopy (XPS) data were used to study the surface. As well as improving the efficiency of the sputtering technique for this surface, a further major benefit is its high stability against electron beam damage as investigated by a quantitative LEED study. Copyright © 2008 John Wiley & Sons, Ltd.
Recent developments in composite connections
Authors: Demonceau Jean‐François , Jaspart Jean‐Pierre , Klinkhammer Ralf , Oerder Ralf , Weynand Klaus , Labory Françoise , Cajot Louis‐Guy 
Published: November 2008

AbstractEurocode 4 [1] suggests design rules for the evaluation of the mechanical properties of steel‐concrete beam‐to‐column composite joints (rotational stiffness, resistance and ductility). These rules cover situations where the joints are subjected to moments and shear forces, but in hogging regions only (negative bending moments). Recently, researches have been conducted on the behaviour of composite joints (Fig. 1) subjected to positive bending moments (called “sagging moments” in the following) and combined bending moments and axial loads; for instance, these loading situations may appear in composite sway frames under conventional loading and exceptional actions (impact, explosion …) leading to the loss of a structural column [2].In the present paper, the Eurocode 4 design rules are extended to joints in sagging regions and to joints subjected to combined bending moments and axial loads and the proposed methods are validated through comparisons with experimental test results. An easy‐to‐use and freely available software for the design of composite joints according to the Eurocode 4 principles is also described.
High‐strength steel fillet welded connections
Authors: Kuhlmann Ulrike , Günther Hans‐Peter , Rasche Christina 
Published: November 2008

AbstractThis paper presents the results of a research project analysing the strength and ductility of welded high‐strength steel connections. Existing design rules according to Eurocode 3 are introduced and discussed showing that these rules are inadequate for high‐strength steel connections for various reasons. Quasi‐static strength tests on fillet welded connections together with numerical simulations are presented. Based on these tests, recommendations for updating the rules of Eurocode 3 are suggested.
Whole‐brain thinking in systems architecting
Authors: Carlo Tony Di , Khoshnevis Behrokh , Udwadia Firdaus 
Published: November 2008

AbstractThis position paper†explores the role of whole‐brain thinking in the context of systems architecting. Brain research indicates that the brain is dual and that each of its hemispheres interprets the world differently; the concept is commonly referred to as right‐brain and left‐brain thinking, or sometimes R‐mode and L‐mode for short. L‐mode denotes step‐by‐step linear thinking. R‐mode is integrative and holistic. It pays to extend this to systems architecting. For example, there may be two ways to look at complexity, analytically and holistically. Step‐by‐step analysis is well suited for low‐dimensional complexity. As complexity increases methodical analytical skills become overwhelmed and we are bogged down, maybe even forced into complacent partial representation—tunnel vision. Learning to “see” the complex may benefit from a shift from the analytical to the holistic, from L‐mode to R‐mode thinking, or a better blending of the two. We begin with a cursory review of brain theory and applications thereof in drawing, management and creativity theory, and then follow up with observations of blended L/R‐mode thinking in the context of systems architecting. Our hope is to distill from these sources whole‐brain mental strategies that may be relevant to systems architects. © 2008 Wiley Periodicals, Inc. Syst Eng
Risk management capability maturity model for complex product systems (CoPS) projects
Authors: Yeo K. T. , Ren Yingtao 
Published: November 2008

AbstractThis paper aims at conceptualizing and developing a multilevel framework for the Risk Management Capability Maturity Model (RM‐CMM), specifically for Complex Product Systems (CoPS) projects. CoPS is a special class of projects, which are high‐value, technology‐ and engineering‐intensive products or systems that are typically used to produce consumer goods and services. The embedded and inherent complexity in terms of task and human relations in CoPS projects can be a major source of risk and can contribute to persistent project challenges, failure, and impairment. There is a need to build a progressive risk management capability to deal with the unique characteristics of these complex projects. The proposed CoPS‐RM‐CMM model defines two broad layers in systems “security” and organizational “robustness.” The understanding of complexity inherent in CoPS projects is drawn from the science of complexity and emergence, which provides additional insights into the management of both predictable and emergent risk in CoPS implementation. The proposed model is also built upon a change management framework, which addresses the risk planning and control processes, organizational and people contexts, and technology contents of CoPS. © 2008 Wiley Periodicals, Inc. Syst Eng
Tricuspid regurgitation in screening for trisomies 21, 18 and 13 and Turner syndrome at 11 + 0 to 13 + 6 weeks of gestation
Authors: Kagan K. O. , Valencia C. , Livanos P. , Wright D. , Nicolaides K. H. 
Published: November 2008

AbstractObjectiveTo investigate the performance of first‐trimester screening for aneuploidies by including assessment of tricuspid blood flow in the combined test of maternal age, fetal nuchal translucency (NT) thickness, fetal heart rate (FHR) and serum free β‐human chorionic gonadotropin (β‐hCG) and pregnancy‐associated plasma protein A (PAPP‐A).MethodScreening by the combined test was performed in singleton pregnancies, including 19 614 with chromosomally normal fetuses or the delivery of a phenotypically normal baby (euploid group), 122 with trisomy 21, 36 with trisomy 18, 20 with trisomy 13 and eight with Turner syndrome. In all cases tricuspid flow was assessed to determine if there was tricuspid regurgitation. We examined the performance of two screening strategies: firstly, assessment of tricuspid flow in all patients and secondly, first‐stage screening using the combined test in all patients followed by second‐stage assessment of tricuspid flow only in those with an intermediate risk of 1 in 51 to 1 in 1000 after the first stage.ResultsTricuspid regurgitation was observed in 0.9% of the euploid fetuses and 55.7%, 33.3% and 30% of the fetuses with trisomies 21, 18 and 13, respectively, and in 37.5% of those with Turner syndrome. In a screening policy based on maternal age, fetal NT, FHR, serum free β‐hCG and PAPP‐A, for a fixed false positive rate of 3% the standardized detection rates were 91% for trisomy 21 and 100% for trisomy 18, trisomy 13 and Turner syndrome. Assessment of tricuspid flow in all pregnancies would increase the detection rate of trisomy 21 to 96%, and the detection rates of trisomy 18, trisomy 13 and Turner syndrome would be 92%, 100% and 100%, respectively. The same detection rates were achieved with the two‐stage strategy—in which it was necessary to assess tricuspid flow in only 15% of the total population—at a false positive rate of 2.4%.ConclusionsAssessment of tricuspid flow improves the performance of first‐trimester screening for trisomy 21. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Ag3Bi14Br21: ein Subbromid mit Bi24+‐Hanteln und Bi95+‐Polyedern – Synthese, Kristallstruktur und Chemische Bindung
Authors: Wahl Bernhard , Ruck Michael 
Published: November 2008

AbstractAg3Bi14Br21: a Subbromide with Bi24+ Dumbbells and Bi95+ Polyhedra – Synthesis, Crystal Structure and Chemical BondingBlack crystals of Ag3Bi14Br21 = (Bi95+)[Ag3Bi3Br153−](Bi2Br62−), the first argentiferous bismuth subhalide, were obtained from a stoichiometric melt of Ag, Bi, and BiBr3. The compound crystallizes in the monoclinic space group P21/m with lattice parameters a = 1277.78(5) pm, b = 1466.87(6) pm, c = 1342.62(5) pm, and β = 108.47(1)° at 110(5) K. In contrast to all other bismuth subhalides that contain an electron‐rich transition metal, the silver atoms are not bonded to bismuth atoms. Instead they are integrated into the anionic bromometallate network, which consists of [MBr6]‐octahedra (M = Ag, Bi) that share edges and vertices. These corrugated $_{\infty}^{2}\rm [Ag_{3}Bi_{3}Br_{15}]^{3-}$ sheets alternate with tessellated layers formed by Bi95+ polycations and hitherto unknown (BiII2Br6)2− groups. The latter anions contain Bi24+ dumbbells (299 pm) and can be represented by the structured formula [Br2BiII(μ–Br)2BiIIBr2]2−. The multi‐center bonding within the Bi95+ cluster and the bent single‐bond in the Bi2 dumbbell can be visualized using the electron localization indicator (ELI‐D).
Synthese und strukturchemische Untersuchungen an molekularen Oxovanadiumphosphonaten
Authors: Wulff‐Molder Dirk , Meisel Manfred 
Published: November 2008

AbstractSynthesis and Structural Studies on Molecular Oxovanadium PhosphonatesSolvothermal syntheses at 373 K in the system (MePPh3)[VO2Cl2]/ RPO3H2 (R = tBu; Ph)/Template (T= Cl−, HCl, OH−; Br−) /MeCN have lead to the already known compound [(VO)6(tBuPO3)8 ⊂ Cl−] (1) [1] as well as to [(VO)6(tBuPO3)8 ⊂ T](T: HCl (2) OH− 3), [(VO)6(PhPO3)8 ⊂ Br−]×solv (4), (Ph3PMe)2[(VO)6(PhPO3)8 ⊂ Cl−]3 (5) with an identical VPO‐core, and [(V3O5)(VO)4(tBuPO3)8 ⊂ NO3−] (6) with seven metal centres. The renewed X‐ray structure analysis of 1 produced evidence, that the {V6P8O24}‐core shows some flexibility and belongs to the enantiomorphic point group O (≡ 432). With the structure data from the compounds 1–5 a geometric model for the flexible contraction of the {V6P8O24}‐core was developed. The calculation of the diameter of the host shell for different degrees of contraction shows that the {V6P8O24}‐core is always too small to incorporate a nitrate ion. This leads to the formation of [(V3O5)(VO)4(tBuPO3)8 ⊂ NO3−] (6) which can be derived topologically from 1. There is no structural similarity between 6 and the seven oxovanadium units containing anion of (Ph4P)2[(V4O7)(V3O5)(PhPO3)6 ⊂ Cl−] [2].The thermal degradation of 1 in air starts at 590 K with the oxidation of the organic groups followed by the formation of β‐(VO)(PO3)2. Possibly these results offer new ways to use oxovanadium phosphonates as precursors of oxovanadium phosphate catalysts.