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101.
In this work, the simulation of earings in cup drawing by means of a recently developed anisotropic combined hardening material model is discussed. The model represents a multiplicative formulation of anisotropic elastoplasticity in the finite strain regime with nonlinear kinematic and isotropic hardening. Plastic anisotropy is described by the use of second-order structure tensors as additional arguments in the representation of the yield function and the plastic flow rule. The evolution equations are integrated by a form of the exponential map that preserves the plastic volume and the symmetry of the internal variables. Finite element simulations of cylindrical cup drawing processes are performed by means of ABAQUS/Standard where the discussed material model has been implemented into a user-defined reduced integration solid-shell element. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
102.
103.
The extraction of stoichiometric ternary K/Si/P, K/Ge/P, and K/Si/As solid mixtures with en/crypt‐222 afforded compounds with binary anions of the respective groups 14/15 elemental combination. Although the analysis of the products turned out to be extremely difficult owing to their intrinsically poor crystallinity and low solubility, we have evidence that one of them contains (SiP6H2)2– anions. Preliminary data from the two other compounds indicate the existence of the heavier Ge/P and Si/As variants as well. The combination of all analytical results, including X‐ray crystallography, energy‐dispersive X‐ray (EDX) spectroscopy, electrospray ionization mass spectrometry (ESI‐MS), and nuclear magnetic resonance (NMR) spectroscopy, point towards the named composition of the anions and their doubly protonated nature. By this, they represent the first binary Zintl anions of the Si/P and Si/As elemental combination and complement the recent endeavors to synthesize binary Zintl anions of the light(er) p‐block elements. We discuss our attempts to elucidate the clusters' identity and provide our results as the most probable interpretation of the data, additionally corroborated by quantum chemical analyses. 相似文献
104.
Conrad A. P. Goodwin Jing Su Thomas E. Albrecht‐Schmitt Anastasia V. Blake Enrique R. Batista Scott R. Daly Stefanie Dehnen William J. Evans Andrew J. Gaunt Stosh A. Kozimor Niels Lichtenberger Brian L. Scott Ping Yang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):12050-12050
105.
Niels Lichtenberger Werner Massa Stefanie Dehnen 《Angewandte Chemie (International ed. in English)》2019,58(10):3222-3226
We present the results from a reactivity study of the binary anion (TlBi3)2? towards Group 12 metal compounds MPh2 (M=Zn, Cd, Hg) to gain access to coordination compounds of polycyclic polypnictide molecules such as Bi73? or Bi113?. The coordination chemistry of these polybismuthide cages has been unprecedented to date, while it has been known for a long time for the lighter Group 15 anions Pn73? (Pn=P, As, Sb). The use of (TlBi3)2?, previously shown to release Tl under certain conditions in situ, resulted in the formation of the first heterometallic polyanion in which a nortricyclane‐type polybismuthide coordinates a transition‐metal atom, [(Bi7)Cd(Bi7)]4?. Reactions with the lighter Group 12 metal precursor yielded the uncommon ternary cluster [(Bi6)Zn3(TlBi5)]4?, most likely representing a reaction intermediate, and at the same time hinting at the formation of the nortricyclane‐shaped cage. Quantum‐chemical studies provide deeper insight into the stability trends of the [(E7)M(E7)]4? anion family and reveal a complex bonding situation in [(Bi6)Zn3(TlBi5)]4?, which features both localized and multi‐center bonding. 相似文献
106.
107.
Driller KM Libnow S Hein M Harms M Wende K Lalk M Michalik D Reinke H Langer P 《Organic & biomolecular chemistry》2008,6(22):4218-4223
N-glycosides of 6H-indolo[2,3-b]quinoxalines were prepared and structurally characterized. The synthesis relies on the cyclocondensation of isatine-N-glycosides with 1,2-diaminobenzenes. Some products exhibit weak cytotoxic activity against human ceratinocytes (HaCaT). 相似文献
108.
Buse C Altmann F Amann B Hauck SM Poulsen Nautrup C Ueffing M Stangassinger M Deeg CA 《Electrophoresis》2008,29(6):1325-1332
There is increasing evidence that a large proportion of dilated cardiomyopathy (DCM) cases are mediated by autoimmune processes. Since DCM is a fatal disorder with rapid aggravation and is the leading cause of heart transplantation, further insights into disease pathogenesis are needed. Recent studies have separated the pathogenic capacity of autoantibodies and initial clinical trials removing such autoantibodies via immunoadsorption have been promising. In order to elucidate the full autoantibody repertoire involved in DCM, we applied an autoantibody screening test using ventricular and atrial proteomes as autoantigenic sources and subsequently tested the autoantibody-binding patterns of sera from dogs with spontaneous DCM. With this method, we detected five potentially DCM-related autoantigens which were identified by MS as being: myosin heavy chain cardiac muscle alpha isoform, alpha cardiac actin, mitochondrial aconitate hydratase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and brain glycogen phosphorylase (GPBB). The recovery of two known DCM autoantigens (myosin heavy chain and alpha cardiac actin) and the discovery of three novel autoantigens (mitochondrial aconitate hydratase, GADPH, and GPBB) underscore the efficacy of this experimental method and the significance of the spontaneous canine DCM model. 相似文献
109.
Stefanie Petermichl 《Proceedings of the American Mathematical Society》2008,136(4):1237-1249
We establish the best possible bound on the norm of the Riesz transforms as operators in the weighted space for in terms of the classical characteristic of the weight.
110.
Huang Y Khartulyari S Morales ME Stanislawska-Sachadyn A Von Feldt JM Whitehead AS Blair IA 《Rapid communications in mass spectrometry : RCM》2008,22(16):2403-2412
Red blood cell (RBC) folate levels are established at the time of erythropoiesis and therefore provide a surrogate biomarker for the average folate status of an individual over the preceding four months. Folates are present as folylpolyglutamates, highly polar molecules that cannot be secreted from the RBCs, and must be converted into their monoglutamate forms prior to analysis. This was accomplished using an individual's plasma pteroylpolyglutamate hydrolase by lysing the RBCs in whole blood at pH 5 in the presence of ascorbic acid. Quantitative conversion of formylated tetrahydrofolate derivatives into the stable 5,10-methenyltetrahydrofolate (5,10-MTHF) form was conducted at pH 1.5 in the presence of [(13)C(5)]-5-formyltetrahydrofolate. The resulting [(13)C(5)]-5,10-MTHF was then used as an internal standard for the formylated forms of tetrahydrofolate that had been converted into 5,10-MTHF as well any 5,10-MTHF that had been present in the original sample. A stable isotope dilution liquid chromatography-multiple reaction monitoring/mass spectrometry method was validated and then used for the accurate and precise quantification of RBC folic acid, 5-methyltetrahydrofolate (5-MTHF), tetrahydrofolate (THF), and 5,10-MTHF. The method was sensitive and robust and was used to assess the relationship between different methylenetetrahydrofolate reductase (MTHFR) 677C>T genotypes and RBC folate phenotypes. Four distinct RBC folate phenotypes could be identified. These were classified according to the relative amounts of individual RBC folates as type I (5-MTHF >95%; THF <5%; 5,10-MTHF <5%), type II (5-MTHF <95%; THF 5% to 20%; 5,10-MTHF <5%), type III (5-MTHF >55%; THF >20%; 5,10-MTHF >5%), and type IV (5-MTHF <55%; THF >20%; 5,10-MTHF >5%). 相似文献