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881.
P.J. von Ranke N.A. de Oliveira V.S.R. de Sousa A. Magnus G. Carvalho 《Journal of magnetism and magnetic materials》2010,322(1):84-87
In this work we present a model to describe the magnetocaloric effect (MCE) in ferrimagnetic arrangements. Our model takes into account the magnetoelastic interactions in the two coupled magnetic sublattices, which can lead to the onset of the first order magnetic phase transition and the giant-MCE. Several profiles of the MCE, such as: the inverse- and giant-MCE were systematically studied. Application of the model to the ferromagnetic compounds GdAl2, Gd5(Ge1.72Si2.28), Gd5(Ge2Si2), and to the ferrimagnetic compound Y3Fe5O12 was performed, showing a good agreement with the experimental data. 相似文献
882.
Jensen FH Beedholm K Wahlberg M Bejder L Madsen PT 《The Journal of the Acoustical Society of America》2012,131(1):582-592
Bottlenose dolphins (Tursiops sp.) depend on frequency-modulated whistles for many aspects of their social behavior, including group cohesion and recognition of familiar individuals. Vocalization amplitude and frequency influences communication range and may be shaped by many ecological and physiological factors including energetic costs. Here, a calibrated GPS-synchronized hydrophone array was used to record the whistles of bottlenose dolphins in a tropical shallow-water environment with high ambient noise levels. Acoustic localization techniques were used to estimate the source levels and energy content of individual whistles. Bottlenose dolphins produced whistles with mean source levels of 146.7 ± 6.2 dB re. 1 μPa(RMS). These were lower than source levels estimated for a population inhabiting the quieter Moray Firth, indicating that dolphins do not necessarily compensate for the high noise levels found in noisy tropical habitats by increasing their source level. Combined with measured transmission loss and noise levels, these source levels provided estimated median communication ranges of 750 m and maximum communication ranges up to 5740 m. Whistles contained less than 17 mJ of acoustic energy, showing that the energetic cost of whistling is small compared to the high metabolic rate of these aquatic mammals, and unlikely to limit the vocal activity of toothed whales. 相似文献
883.
Pavlo Nikolaienko Prof. Dr. Magnus Rueping 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(8):2620-2623
The straightforward introduction of the trifluoromethylseleno group into aromatic and heteroaromatic compounds is accomplished by the utilization of readily available aryldiazonium tetrafluoroborates, potassium selenocyanate, and Ruppert–Prakash reagent. The reaction tolerates a wide range of aromatic and heteroaromatic diazonium salts and is also amenable to the synthesis of pentafluoroethyl selenoethers. Furthermore, the methodology can be applied directly starting from anilines. 相似文献
884.
Dr. Yunfei Cai Dr. Yurong Tang Prof. Dr. Magnus Rueping 《Angewandte Chemie (International ed. in English)》2016,55(45):14126-14130
The first catalytic asymmetric Piancatelli reaction is reported. Catalyzed by a chiral Brønsted acid, the rearrangement of a wide range of furylcarbinols with a series of aniline derivatives provides valuable aminocyclopentenones in high yields as well as excellent enantioselectivities and diastereoselectivities. The high value of the aza‐Piancatelli rearrangement was demonstrated by the synthesis of a cyclopentane‐based hNK1 antagonist analogue. 相似文献
885.
886.
Lin Guo Prof. Dr. Magnus Rueping 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(47):16787-16790
A new and efficient nickel‐catalyzed decarbonylative borylation reaction of carboxylic acid esters with bis(pinacolato)‐diboron has been developed. This transformation allows access to structurally diverse aryl as well as alkenyl and alkyl boronate esters with high reactivity, broad substrate scope, and excellent functional‐group tolerance. Further experiments show that this protocol can be carried out on a gram scale and applied to orthogonal synthetic strategies. 相似文献
887.
Dr. Lulu Fan Jiaqi Jia Dr. Hong Hou Dr. Quentin Lefebvre Prof. Dr. Magnus Rueping 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(46):16437-16440
A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C?O bond cleavage is described for the first time. A wide range of aryl triflates as well as aryl mesylates, tosylates and alkenyl triflates afford the corresponding products in good to excellent yields. 相似文献
888.
889.
A new silicon-based protecting group for primary amines has been developed. Its usefulness is illustrated in a simple synthesis of an alkylated amino acid derivative. 相似文献
890.