bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zweidimensionale NMR‐Spektroskopie, Grundlagen und Übersicht über die Experimente
Authors: Kessler Horst , Gehrke Matthias , Griesinger Christian 
Published: July 2007

AbstractEine genaue Kenntnis der Struktur, Dynamik und Reaktionsweise von Molekülen ist der Schlüssel zum Verständnis ihrer Funktionen und Eigenschaften. Die NMR‐Spektroskopie hat sich durch die Einführung zweidimensionaler Verfahren zur bedeutendsten Methode entwickelt, um derartige Informationen über Moleküle in Lösung zu erhalten. Es steht nunmehr ein ganzes Arsenal von Aufnahmetechniken zur Verfügung, deren erfolgreiche Anwendung aber nicht nur die entsprechende apparative Ausstattung, sondern auch die richtige Auswahl der Experimente einschließlich der optimalen Meßparameter und natürlich auch die sorgfältige Auswertung der Spektren voraussetzt. In diesem Beitrag werden die Grundlagen der modernen NMR‐Spektroskopie vorgestellt, und es wird gezeigt, daß es mit dem Produktoperatorformalismus möglich ist, die Pulsfolgen der NMR‐Spektroskopie qualitativ und quantitativ zu verstehen. Nur ganz wenige, leicht verständliche Annahmen muß ein potentieller Anwender dieser Methoden kennenlernen, um mit ihnen vertraut zu werden. Wir wollen den Produktoperatorformalismus ebenso wie die für das Verständnis der Pulsfolgen unabdingbaren Phasencyclen auf einfache Weise einführen und den Umgang mit ihnen bei der Besprechung verschiedener 2D‐NMR‐Techniken üben. Eine Übersicht über die wichtigsten Pulstechniken bildet den zweiten Teil des Beitrags.
Elektronendichte, Deformationsdichte und chemische Bindung
Authors: Schwarz W. H. Eugen , Ruedenberg Klaus , Mensching Lothar , Miller Lance L. , Jacobson R. , Valtazanos Petros , Von Niessen Wolfgang 
Published: July 2007

Freie Atome sind nicht notwendigerweise rund, und Atome in einem Molekül sind durch ihre Position und ihre Ausrichtung bestimmt. Erst wenn dies berücksichtigt wird, erhält man gut interpretierbare Differenzdichten. So führt für HF, bei dem konventionelle Differenzdichten die experimentell gesicherte kovalente Bindung nicht erklären können, ein ausgerichtetes F‐Atom zu nebenstehender Differenzdichtekarte. magnified image
Von 2,5‐Dihydropyrazinen zu 2H‐1,4‐Diazepinen und von Benzodihydroarenen zu Benzocyclohepten‐Derivaten, Strukturvarianten des Antidepressivums Protriptylin
Authors: Schöllkopf Ulrich , Mittendorf Joachim 
Published: July 2007

Eine Hetero‐Norcaradien‐Cycloheptatrien‐Umlagerung und eine außergewöhnlich schnelle transanulare [1,5]‐sigmatrope Wasserstoffverschiebung sind die Schlüsselschritte bei der baseinduzierten Ringerweiterung der Bislactimether 1 zu den 2H‐1,4‐Diazepinen 2. Die Ringerweiterung ist auch bei analogen all‐Kohlenstoffverbindungen möglich und führt beispielsweise von Dihydroanthracenen zu neuen Strukturvarianten des Antidepressivums Protriptylin wie 3. Beispiele für R1 – R3: H, Me, OMe, Ph, CH2Ph. magnified image
Synthese und Struktur neuer Cu‐Cluster: [Cu30−xSe15(PiPr3)12] (x = 0,1) und [Cu36Se18(PtBu3)12]
Authors: Fenske Dieter , Kraustscheid Harald , Balter Silke 
Published: July 2007

Anders als das System Phosphan/AgCl reagiert das System Phosphan/CuCl mit Se(SiMe3)2 unterhalb 20°C in Ausbeuten von 60% zu metallreichen Clusterkomplexen. Oberhalb 100°C bilden sich dagegen binäre Kupferselenide. Die Verbindungen 1–3 konnten kristallstrukturanalytisch charakterisiert werden. Dabei handelt es sich um die größten bisher bekannten Cu‐Clusterverbindungen. Die Strukturen von 1 und 2 zeigen, daß ein Clustergerüst vorliegt, dessen Polyederflächen von μ4‐Se‐, μ5‐Se‐ und μ6‐Se‐Liganden bedeckt sind.magnified image
Kooperative Wechselwirkungen bei der molekularen Erkennung — die Bindung von Diaminen an eine Tetracarbonsäure
Authors: Ebmeyer Frank , Rebek Julius 
Published: July 2007

Ein allosterischer Effekt scheint dafür verantwortlich zu sein, daß das Gastmolekül 1 mit Hydrazin, Ethylendiamin und 1,4‐Diazabicyclo[2.2.2]octan (DABCO) 1:2‐Komplexe bildet, wobei die zweite Assoziationskonstante um den Faktor 50, 200 bzw. 2 größer ist als die erste. Diese positive kooperative Wechselwirkung ist in den ersten beiden Fällen viel stärker als bei ditopen Kronenethern.magnified image
Retrofit of a H2 S selective amine absorber using MellapakPlus structured packing
Authors: Shiveler Glenn , Solis Geronimo Sixtos , Peña Gonzalez Luis Horacio , Bueno Marcelo Lara 
Published: July 2007

AbstractA major natural gas amine sweetening plant was retrofitted with high‐performance MellapakPlus structured packing in place of valve trays in its 1219 mm (48 inch) diameter amine absorber in order to increase gas capacity and to selectively remove H2S and improve slippage of CO2 using generic methyldiethanolamine (MDEA) amine solvent. The retrofit of the amine absorber was successful, and it achieved the primary objective of improved gas handling capacity and increased H2S selectivity. During the six months of operation, the unit regularly achieved 80% slippage of CO2 while selectively removing H2S to pipeline specification. This paper provides an overview of the gas sweetening plant operation following the retrofit, with performance data obtained for variable inlet feed conditions. This paper includes observations regarding changes in amine quality, reduction of amine consumption, issues with amine degradation, amine salt contamination, experience with minor amounts of fouling and the utilization of an anti‐foaming agent. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Continuous operation of a chemical heat pump
Authors: Ogura Hironao , Yasuda Sotaro , Otsubo Yasufumi , Mujumdar Arun S. 
Published: July 2007

AbstractIn this experimental study, chemical heat pump (CHP) characteristics for heat storage and heat release in repetitive operation were examined. The input/output heat of the CHP in repetitive operation was found to be controlled by the special pressure adjustment procedure such as instant vacuuming or additional vacuuming for pressure‐temperature control of the CHP reactor. In the case of the CaO/H2O/Ca(OH)2 hydration/dehydration system, the CHP is found to produce controlled‐temperature hot/cold heat in a repetitive operation using chemically stored energy during both heat‐storing and heat‐releasing steps. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Dispersion of nanoscale BaTiO3 suspensions by a combination of chemical and mechanical grinding/mixing processes
Authors: Ying Kuo‐Liang , Hsieh Tsung‐Eong 
Published: July 2007

AbstractThe colloidal stability of aqueous nanometer‐ and micrometer‐scale barium titanate (BaTiO3) utilizing poly (methacrylic acid) (PMAA‐Na) and polyacrylamide/(α‐N,N‐dimethyl‐N‐acryloyloxyethyl)ammonium ethanate (PDAAE) was investigated. In addition to chemical dispersants, the effects of mechanical milling using either conventional ball milling or nanogrinding/‐mixing on the dispersion of BaTiO3 suspensions were also studied. Characterization of the particle size distribution (d50), viscosity, and morphology of BaTiO3 particles in the suspensions revealed that a sole chemical dispersant or mechanical milling was insufficient to achieve nanometer‐scale dispersion. The best dispersion results were obtained with a combination of PMAA‐Na dispersant and nanogrinding/‐mixing, which could provide sufficient electronic repulsive force and shear force to disperse the 80‐nm BaTiO3 powders uniformly in the aqueous suspension. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Isothermal crystallization kinetics and melting behaviors of nanocomposites of poly(trimethylene terephthalate) filled with nano‐CaCO3
Authors: Run Mingtao , Yao Chenguang , Wang Yingjin , Gao Jungang 
Published: July 2007

AbstractThe isothermal crystallization and subsequent melting behavior of poly(trimethylene terephthalate) (PTT) composites filled with nano‐CaCO3 were investigated at designated temperatures with differential scanning calorimetry. The Avrami equation was used to fit the isothermal crystallization. The Avrami exponents were determined to be 2–3 for the neat PTT and PTT/CaCO3 composites. The particles of nano‐CaCO3, acting as nucleating agents in the composites, accelerated the crystallization rate, with the half‐time of crystallization decreasing or the growth rate constant (involving both nucleation and growth rate parameters) increasing. The crystallization activation energy calculated from the Arrhenius formula was reduced as the nano‐CaCO3 content increased from 0 to 2%, and this suggested that nano‐CaCO3 made the molecular chains of PTT easier to crystallize during the isothermal crystallization process. Subsequent melting scans of the isothermally crystallized composites exhibited triple or double melting endotherms: the greater the content was of nano‐CaCO3, the lower the temperature was of the melting peak. The degree of crystallization deduced from the melt enthalpy of composites with the proper concentration of nano‐CaCO3 was higher than that of pure PTT, but it was lower when the nano‐CaCO3 concentration was more than 2%. The transmission electron microscopy pictures suggested that the dispersion state of nano‐CaCO3 particles in the polymer matrix was even when its concentration was no more than 2%, whereas some agglomeration occurred when its concentration was 4%. Polarized microscopy pictures showed that much smaller or less perfect crystals formed in the composites because of the interaction between the molecular chains and nano‐CaCO3 particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Dye–fiber interactions in PET fibers: Hydrogen bonding studied by IR‐spectroscopy
Authors: Clerck Karen De , Rahier Hubert , Mele Bruno Van , Westbroek Philippe , Kiekens Paul 
Published: July 2007

AbstractDye–fiber interactions are studied in poly (ethylene terephthalate) fibers by FT‐IR spectroscopy. It is shown for the first time that DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) serves as an easy applicable and accurate technique for the study of fibrous structures. This article focuses on the possible hydrogen bond interactions in the dye–fiber system, where the PET fibers are dyed with anthraquinone‐based disperse dyes. The dyes and related anthraquinone structures are studied in both the dilute solution state, the solid state, and as present in the PET fibers. It is proven that 1‐amino anthraquinones show strong “chelate‐type” intramolecular hydrogen bonding in all three states. In the fibers an important supplementary intermolecular hydrogen bonding with the CO groups in the PET fiber is observed. The extend of hydrogen bonding seems to be prone to dye concentration variations. Further analysis by modulated differential scanning calorimetry links the hydrogen bonding to an intrinsic plasticizing effect of the dyes affecting the dye diffusion process. This thus offers a tool for the fundamental understanding of the dyeing process and possible observed differences in dyeing behavior in dye–fiber systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Fluorinated polyether additives to improve the performance of urea–formaldehyde adhesives for wood panels
Authors: Mansouri H. R. , Thomas R. R. , Garnier S. , Pizzi A. 
Published: July 2007

AbstractSmall amounts of fluorinated polyethers, and in particular a nonionic fluorinated polyether, can upgrade considerably the cold‐water swelling and internal bond strength of wood particleboard bonded with urea–formaldehyde (UF) resins. The effect is maximized at an additive concentration of about 0.1 wt % with respect to the adhesive resin solid content. The effect of the fluorinated polyether appears to be greater with older UF resins, which have a more pronounced colloidal state. The mechanism appears to be somewhat related to the reduction of the interfacial tension of the resins, with improved substrate wetting leading to better adhesion. The addition of a fluorinated polyether well in advance of resin use further enhances the improvement. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Effects of ultrasonic oscillations on rheological behavior and mechanical properties of novel propylene‐based plastomers
Authors: Peng Bo , Wu Hong , Guo Shaoyun , Lai Shih‐Yaw , Jow Jinder 
Published: July 2007

AbstractThe effects of ultrasonic oscillations on the die pressure, productivity of extrusion, melt apparent viscosity, melt surface appearance, and die swell of novel propylene‐based plastomers were studied in a specially designed ultrasonic oscillations extrusion system developed in our laboratory. The effects of ultrasonic oscillations on molecular weights, tensile strength, and dynamic mechanical properties of extrudates were also studied. The experimental results showed that the presence of ultrasonic oscillations during extrusion could significantly increase the productivity of plastomers at the same die pressure, and reduce die swell and melt fracture such as sharkskin at a given screw rotation speed. The die pressure and apparent viscosity of plastomers remarkably decreased with increasing ultrasonic intensity. Introduction of ultrasonic oscillations into plastomer melts can improve their processibility. The possible mechanism for ultrasonic improvement of rheological behavior was also proposed in this article. Under certain conditions, ultrasound‐assisted extrusion could slightly decrease the glass transition temperature (Tg) and storage modulus of plastomers due to the minor reduction in molecular weights, but showed no significant impact on yield strength and strength at break. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Fiber breakage and dispersion in carbon‐fiber‐reinforced nylon 6/clay nanocomposites
Authors: Zhou Hu , Qian Zhongzhong , Meng Xiangfu , Ding Yanfen , Zhang Shimin , Yang Mingshu 
Published: July 2007

AbstractIn this paper, short carbon‐fiber‐reinforced nylon 6/clay nanocomposites are prepared via melt compounding, and fiber breakage and dispersion during processing are studied. The influences of clay and processing conditions on fiber breakage and dispersion are taken into consideration. It is found that the presence of organoclay can improve fiber dispersion, which is due to dispersion at the nanoscale of exfoliated clay sheets with large aspect ratio. The bimodal distribution of fiber length is observed in fiber‐reinforced nanocomposites, which is similar to that in conventional fiber‐reinforced composites. The improvement of fiber breakage at moderate organoclay loadings is also observed, which is ascribed to the rheological and lubricating effects induced by organoclay. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Liquid chromatography/electrospray ionization mass spectrometry method for the determination of the active metabolite M‐1 of suplatast tosilate in human plasma
Authors: Ding Li , Ding Likun , Zhou Xia , Yang Lin , Wen Aidong 
Published: July 2007

AbstractA liquid chromatography/electrospray ionization mass spectrometry (LC/ESIMS) method for the determination of 4‐(3‐ethoxy‐2‐hydroxypropoxy) acrylanilide (M‐1), the active metabolite of suplatast tosilate, in human plasma was established. Plasma samples were extracted with diethyl ether, separated on a C18 column with a mobile phase of acetonitrile–10 mm ammonium acetate solution containing 0.1% formic acid (28:72, v/v) and detected by ESIMS. The method was linear over the concentration range 0.15–60.0 ng/mL. The lowest limit of quantification was 0.15 ng/mL. The intra‐ and inter‐run relative standard deviations obtained from three validation runs were all less than 8.6%, and the intra‐ and inter‐run relative errors were all less than 3.1%. The method was successfully applied for the evaluation of pharmacokinetic profiles of M‐1 in healthy volunteers. Copyright © 2007 John Wiley & Sons, Ltd.
Emulation of Racemase Activity by Employing a Pair of Stereocomplementary Biocatalysts
Authors: Gruber Christian C. , Nestl Bettina M. , Gross Johannes , Hildebrandt Petra , Bornscheuer Uwe T. , Faber Kurt , Kroutil Wolfgang 
Published: July 2007

AbstractRacemization is the key step to turn a kinetic resolution process into dynamic resolution. A general strategy for racemization under mild reaction conditions by employing stereoselective biocatalysts is presented, in which racemization is achieved by employing a pair of stereocomplementary biocatalysts that reversibly interconvert an sp3 to a sp2 center. The formal interconversion of the enantiomers proceeds via a prochiral sp2 intermediate the formation of which is catalyzed either by two stereocomplementary enzymes or by a single enzyme with low stereoselectivity. By choosing appropriate reaction conditions, the amount of the prochiral intermediate is kept to a minimum. This general strategy, which is applicable to redox enzymes (e.g., by acting on R2CHOH and R2CHNHR groups) and lyase‐catalyzed addition–elimination reactions, was proven for the racemization of secondary alcohols by employing alcohol dehydrogenases. Thus, enantiopure chiral alcohols were used as model substrates and were racemized either with highly stereoselective biocatalysts or by using (rarely found) non‐selective enzymes.
Recent Advances in the Benzannulation of Substituted 3‐Alkoxycarbonyl‐3,5‐hexadienoic Acids and 3‐Alkoxycarbonylhex‐3‐en‐5‐ynoic Acids to Polysubstituted Aromatics
Authors: Serra Stefano , Fuganti Claudio , Brenna Elisabetta 
Published: July 2007

AbstractThe benzannulation reactions of substituted 3‐alkoxycarbonyl‐3,5‐hexadienoic and 3‐alkoxycarbonylhex‐3‐en‐5‐ynoic acids offer a straightforward access to various polysubstituted aromatic compounds. The process is very flexible, and can be applied to the regiospecific preparation of oligoaryls, naphthalenes, ring‐fused heterocycles, chiral tetrahydronaphthalenes, C‐aryl‐glycosides and many natural products of different structure. In this Concept article, we highlight the potential of this annulation reaction by illustration of our recent contribution to this field, as well as the studies previous reported by others.
Competitive advantages of the kaisha
Authors: Leonard Jim 
Published: July 2007

AbstractEditor's Note: Former Competitive Intelligencer editor, Jim Leonard, attended the Japanese Business Study Program (JBSP) in October, 1989. J B S e sponsored by MITI, guides 50 US, Canadian, and EEC people around Japan for 23 days to learn about Japanese business, culture, markets, and mindsets. This article is a revised excerpt from Jim? report on his impression of Japan and the JBSP program.
Processing ideas: An argument for useful text management software
Authors: Meade Bill 
Published: July 2007

AbstractLow cost, personal computer (PC) based software adapted for competitive intelligence (CI) use can frustrate users because they appear to offer only slightly mare than the sorting and search functions of word processing software. What we would prefer is the capability of finding and manipulating ideas rather than words. The ability to manipulate ideas gives us the machine assisted ability to glean insight from raw text.Those new to the CI field may not yet know what analytical power they would like to possess as CI managers. The mystique of computers and their software sometimes creates the belief that they can do anything: we need only to be smart enough to use them. This thinking leads us to focus on what they can do, instead of what they could do. And we need more power from our software.I asked Bill Meade to comment on the problems associated with our use of text management software. Here he shares his views of our analytical limitations and what software vendors should do about it. Glenn S. Omura.
Corporate marketing services
Authors: Galvin Carol 
Published: July 2007

AbstractCarol Galvin from Digital Equipment Corporation, was the guest speaker at the June 9,1992 meeting of the Boston Chapter. A Marketing Consultant incorporate Marketing Services, she is the focal point for acquisition, management, and dissemination of marketing and competitive information. Corporate Marketing Services (CMS) reports to the Vice President of Corporate Marketing Planning. This column is based on her remarks. Jennifer S. Swanson.
Network security assessment guide
Authors: Brotby W. Krag 
Published: July 2007

AbstractElectronic data could be your firm's most valuable asset, but information theft and illegal/unethical counterintelligence loom as constant threats. Here is a step‐by‐step guide for performing a security checkup on your computer networks. The process includes physical inspection and interviews with security and information systems personnel. A questionnaire is provided for the inspection and interview process, along with a guide to analyzing and interpreting the results. © 1996 John Wiley & sons. Inc.
Competitive intelligence in china: A case study
Authors: Li Zhengzhong , Dong Yu 
Published: July 2007

AbstractCompetitive intelligence is a new discipline in China, where, despite a booming economy, many aspects of competitive business remain novel. The authors provide a look into how a large, state‐owned enterprise applied CI to adapt to the presence of market competition, providing insight into how Chinese companies appraise the competitive strength of competitors and use this information to create competitive strategies, as well as the emerging role of university academics as business consultants. © 1997 John Wiley & Sons, Inc.
Achat ou téléchargement illégal de la musique chez les consommateurs: Le rôle des réponses à l'artiste et à la musique
Authors: Ouellet Jean‐François 
Published: July 2007

AbstractBased on qualitative and quantitative surveys, I show that consumer responses toward a particular song and toward its performer(s) play distinct roles in explaining consumer choices to either buy or illegally download that song. The various types of consumer responses to songs and artists are first identified through qualitative research and then validated through exploratory and confirmatory factor analyses (CFA) of survey data. While consumer responses to music explain the need to reexperience and acquire the song, consumer responses to performers explain purchase over illegal downloading. Copyright © 2007 ASAC. Published by John Wiley & Sons, Ltd.