Carbon nanotube-dependent synthesis of armchair graphene nanoribbons

Sub-nanometer armchair graphene nanoribbons(GNRs)with moderate band gap have great potential towards novel nanodevices.GNRs can be synthesized in the confined t...     

Untersuchungen am Verdauungstrakt von Reh, Damhirsch und Mufflon

Zusammenfassung In Mitteilung 4 wurden die Konzentrationen an Fermentationsprodukren (FFS, NH₄⁺ und freie Aminosäuren) sowie das Fermentationsmuster im Pansen von Reh, Damhirsch und Mufflon aus zwei Gebieten zur gleichen Jahreszeit (Herbst) bestimmt.Während zwischen der Höhe der Fermentationsprodukte sowie der molaren Verteilung der FFS im Pansen von Reh und Mufflon aus Gebiet B signifikante Unterschiede zu beobachten waren, die Rückschlüsse auf den unterschiedlichen Äsungstyp zuließen, stimmten die Werte der drei Species aus Gebiet A überein.Die erhaltenen Daten wurden mit den Werten der Rohnährstoffanalyse (Mitt. 2) und den Angaben über die mikrobielle Besiedlung (Mitt. 3) im Panseninhalt dieser Tiere verglichen.

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Summary Communication 4 shows the concentration of fermentation products (FFA [free fatty acids], NH₄⁺ and free amino acids) as well as the fermentation pattern in the rumen of roe deer, fallow deer and mouflon studied in two areas at the same season (autumn).Concerning the amount of fermentation products and the molar percentage of FFA, we observed significant differences between the rumen contents of roe deer and mouflon belonging to habitat B, and were able to derive some conclusions about their different feeding behaviour. In area A, the values for the three species were quite similar.The results of our investigation were compared with the information on the crude nutrient content (report 2) and the micro-organisms living in the rumen of the animals (report 3).

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Résumé Cette quatrième communication est consacrée à la détermination des concentrations de produits de fermentation (acides gras volatils, NH₄⁺ et acides aminés libres) de même que de l'échantillon de fermentation obtenus en automne dans la panse de chevreuils, daims et mouflons provenant de deux territoires différents.Tandis que des différences significatives étaient observées entre l'abondance des produits de fermentation et la répartition molaire des acides gras volatils dans la panse des chevreuils et celle des mouflons du territoire B, différences qui suggéraient un régime alimentaire distinct, les valeurs obtenues dans le territoire A étaient analogues pour les trois espèces.Les données obtenues furent comparées avec celles de l'analyse des aliments bruts (communication N^o 2) et celles des populations microbiennes (communication n^o 3) des contenus stomacaux de ces différents animaux.

     

High-performance carbon nanotube field effect transistors with a thin gate dielectric based on a self-assembled monolayer

Individual single-walled carbon nanotube (SWCNT) field effect transistors (FETs) with a 2 nm thick silane-based organic self-assembled monolayer (SAM) gate dielectric have been manufactured. The FETs exhibit a unique combination of excellent device performance parameters. In particular, they operate with a gate-source voltage of only -1 V and exhibit good saturation, large transconductance, and small hysteresis (相似文献   

On the costs and benefits of emotional labor: A meta-analysis of three decades of research.

This article provides a quantitative review of the link of emotional labor (emotion–rule dissonance, surface acting, and deep acting) with well-being and performance outcomes. The meta-analysis is based on 494 individual correlations drawn from a final sample of 95 independent studies. Results revealed substantial relationships of emotion–rule dissonance and surface acting with indicators of impaired well-being (ρs between .39 and .48) and job attitudes (ρs between ?.24 and ?.40) and a small negative relationship with performance outcomes (ρs between ?.20 and ?.05). Overall, deep acting displayed weak relationships with indicators of impaired well-being and job attitudes but positive relationships with emotional performance and customer satisfaction (ρs .18 and .37). A meta-analytic regression analysis provides information on the unique contribution of emotion–rule dissonance, surface acting, and deep acting in statistically predicting well-being and performance outcomes. Furthermore, a mediation analysis confirms theoretical models of emotional labor which suggest that surface acting partially mediates the relationship of emotion–rule dissonance with well-being. Implications for future research as well as pragmatic ramifications for organizational practices are discussed in conclusion. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A multiprocess account of hindsight bias in children.

In hindsight, that is, after receiving the correct answers to difficult questions, people's recall of their own prior answers tends to be biased toward the correct answers. We tested 139 participants from 3 age groups (9- and 12-year-olds and adults) in a hindsight-bias paradigm and found that all groups showed hindsight bias. Multinomial model-based analyses indicated that all age groups used the correct answers to reconstruct their original answers. In addition, the youngest group showed memory impairment caused by the presentation of the correct answers as well as an increased belief that they knew the correct answers all along. These results support a multiprocess explanation of hindsight bias in children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of magnetic properties of few nm sized FePt crystalline particles by characterizing the intrinsic atom order using aberration corrected S/TEM

Hard-magnetic nanomaterials like nanoparticles of FePt are of great interest because of their promising potential for data storage applications. The magnetic properties of FePt structures strongly differ whether the crystal phases are face centered cubic (fcc) or face centered tetragonal (fct). We evaluated aberration corrected HRTEM, electron diffraction and aberration corrected HAADF-STEM as methods to measure the chemical degree of order S that describes the ordering of Pt and Fe atoms within the crystals unit cells. S/TEM experiments are accompanied by image calculations. The findings are compared with results obtained from X-ray diffraction on a FePt film. Our results show that STEM is a reasonable fast approach over HRTEM and electron diffraction to locally determine the chemical degree of order S.     

Untersuchungen am Verdauungstrakt von Reh, Damhirsch und Mufflon

Zusammenfassung Die Untersuchungen der chemischen Zusammensetzung des Panseninhaltes von Reh-, Dam- und Muffelwild zweier Lebensräume Süddeutschlands in der Zeit beginnender Äsungsverknappung ergaben, daß nicht in jedem Gebiet zu jeder Jahreszeit die verschiedenen Species die dem vertretenen Äsungstyp entsprechenden Rohnährstoffgehalte im Pansen aufweisen.So enthielt der Panseninhalt des Konzentratselektierers Reh eine ähnliche Rohnährstoffzusammensetzung wie der des Rauhfutterfressers Mufflon im Gebiet A; etwa 25% Rohprotein und 24% Rohfaser in der Trockensubstanz. Im Gebiet B überstieg der Rohproteingehalt im Pansen des Rehes mit 29% weit die Werte des Mufflon mit 18% während die Rohfaserkonzentrationen mit 20% beim Reh wesentlich niedriger als beim Mufflon mit 34% in der Panseninhalt-Trockenmasse lagen. Das Damwild in Gebiet A unterscheidet sich in seinen Rohnährstoffdaten im Panseninhalt zu dieser Jahreszeit nicht von denen des Reh- und Muffelwildes, während die zwei untersuchten Stücke Damwild aus Gebiet B etwa eine Mittelstellung zwischen Reh- und Mufflon einnahmen.

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Summary According to our studies on the chemical composition of the rumen ingesta from roe deer, fallow deer and mouflon living in two habitats in South Germany collected in the autumn, the beginning of the season of grazing scarcity, it has been found that in each region and season the three species do not show the crude nutritive substances in the rumen corresponding to the type of grazing they were on. In region A, the rumen content of the roe deer, a highly selective browser, had a composition of crude nutritive substances similar to that of the mouflon, a nonselective grazer: about 25% raw protein and 24% crude fibre in the dry matter. In region B, the raw protein content of the roe deer rumen (29%) far exceeded that of the mouflon (18%), while the crude fibre concentration of 20% in the roe deer was considerably less than that of the mouflon with 34%. The fallow deer in region A were indistinguishable from the roe deer and mouflon as regards rumen content but the two animals examined in region B occupied a position between that of the roe deer and the mouflon. The paper discusses possible explanations of these observations.

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Résumé L'étude de la composition chimique, au début de la période de disette alimentaire, du contenu stomacal de chevreuils, de daims et de mouflons provenant de deux territoires du Sud de l'Allemagne montre que l'on ne retrouve pas, dans la panse des différentes espèces considérées et à cette saison, les matières brutes correspondant au type de nourriture que l'on rencontre dans ces deux territoires.Ainsi, dans le territoire A, le contenu stomacal du Chevreuil, espèce éclectique s'il en est, révéla une composition en matière brute analogue à celle du Mouflon, consommateur caractérisé d'aliments coriaces, soit 25% de protéines brutes et 24% de fibres brutes. Dans le territoire A, la teneur en protéines brutes dans la panse du Chevreuil (29%) dépassait celle du Mouflon (18%) tandis que la teneur en fibres brutes n'atteignait que 20% chez le Chevreuil contre 34% chez le Mouflon. Dans le territoire B, les daims ne se distinguaient pas des chevreuils et des mouflons en ce qui concernait la teneur en matières brutes, tandis que les deux daims examinés dans le territoire B montraient une position intermédiaire entre le Mouflon et le Chevreuil.

     

Development and evaluation of methods for determining the pattern of functionalization in sodium carboxymethylcelluloses

Sodium carboxymethylcellulose (NaCMC) with varying degrees of substitution (DS) was investigated with different analytical methods in order to characterize the functional group distribution. The following methods were tested and adapted: high-resolution ¹³C NMR spectroscopy in the solid state (¹³C CP/MAS NMR) and ¹³C NMR spectroscopy on solutions of NaCMC samples with a reduced molar mass. Partial degradation was accomplished by ultrasonic means and with the enzyme endoglucanase. Combining the two techniques resulted in the greatest reduction in molar mass and hence in the best spectral resolution. Analysis of the NaCMC fragments following ultrasonic and/or endoglucanase degradation also reveals another interesting experimental finding. It appears that ultrasonic degradation is favored at unsubstituted areas near the center of the chain. These methods were compared with the following already familiar techniques of analysis: titrimetric techniques; ¹³C and ¹H NMR spectroscopy as well as HPLC on completely hydrolysed solutions (hydrolysis with perchloric acid, trifluoroacetic acid and sulfuric acid). All of the methods characterize the samples as a series with increasing DS, the values of which range from 0.9 to 2.4. Methods that permit analysis of the partial degree of substitution produced the distribution x₂ > x₆ > x₃. Therefore, they are in principle suited for determining the functionalization pattern of the NaCMC samples relative to one another. The most suitable method can therefore be selected according to the objectives and the apparatus available. However, the measured values do exhibit considerable spread, variances of approx. 20%, thus, place restrictions on using the values of DS or x_i in absolute comparisons beyond these methods.     

Interface Formation in the US-Wedge/Wedge-Bond Process of AlSi1/CuNiAu Contacts

Interface formation between 25-μm AlSi1 wire and flash-Au substrate metallization during a bonding time of 50 ms has been investigated. Only a few milliseconds after the ultrasonic power is switched on, intermetallic phase growth starts, continuing until the end of the wire-bonding process. During the entire bonding time, the fraction of the interface covered with Au₈Al₃ increases, and at the end of the bonding time, the interface is nearly completely covered with that phase. Finite-element modeling (FEM) of the temperature in the interface region indicates maximum temperatures well below 100°C, thus making solely thermally activated intermetallic phase growth impossible. However, it is demonstrated that the phase growth observed during the ultrasonic wire-bonding process could result from an accelerated diffusion process caused by a higher vacancy concentration. The accelerated diffusion process would have an activation energy Q of 0.36 eV.