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排序方式: 共有268条查询结果,搜索用时 437 毫秒
51.
Benjamin Heuwers Dominik Quitmann Frank Katzenberg Joerg C. Tiller 《Macromolecular rapid communications》2012,33(18):1517-1522
Lightly cross‐linked natural rubber (NR, cis‐1,4‐polyisoprene) was found to be an exceptional cold programmable shape memory polymer (SMP) with strain storage of up to 1000%. These networks are stabilized by strain‐induced crystals. Here, we explore the influence of mechanical stress applied perpendicular to the elongation direction of the network on the stability of these crystals. We found that the material recovers its original shape at a critical transverse stress. It could be shown that this is due to a disruption of the strain‐stabilizing crystals, which represents a completely new trigger for SMPs. The variation of transverse stress allows tuning of the trigger temperature Ttrig(σ) in a range of 45 to 0 °C, which is the first example of manipulating the transition of a crystal‐stabilized SMP after programming. 相似文献
52.
53.
The BGK model of rarefied gas dynamics [1] is solved numerically by using the Finite Pointset Method (FPM) [2], which is a particle method developed at the ITWM Kaiserslautern. For the implementation a semilagrangian scheme [3] is used. Numerical results are shown on the example of a Shock tube problem for different Knudsen numbers. The solutions are compared to the solutions of exact Euler in the case of small Knudsen numbers and to DSMC solutions for higher Knudsen numbers. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
54.
Sediment transport involves fluid flow in two different regions. In the free flow domain, the flow is governed by the viscous Newtonian fluid; sediment only occurs as suspended particles. In the porous domain however, the flow is governed by the pore geometry of the porous skeleton consisting of sedimented grains. In nature, the interface between these two domains is not a no-slip boundary for the free flow. In this study, we quantify how sediment transport is affected by the interaction of the two different flows. We do this by comparing fluid flow in no-slip bounded flow channels to fluid flow in channels containing both a free and a porous domain. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
55.
Himabindu Nandivada Hsien‐Yeh Chen Joerg Lahann 《Macromolecular rapid communications》2005,26(22):1794-1799
Summary: The vapor‐based synthesis and characterization of a reactive polymer, poly[(4‐formyl‐p‐xylylene)‐co‐(p‐xylylene)] ( 1 ), have been reported. The reactive polymer coating enables the immobilization of oligosaccharides via the chemoselective aldehyde‐hydrazide coupling reaction.
56.
Aimo Kannt Sridharan Rajagopal Mahanandeesha S. Hallur Indu Swamy Rajendra Kristam Saravanakumar Dhakshinamoorthy Joerg Czech Gernot Zech Herman Schreuder Sven Ruf 《Molecules (Basel, Switzerland)》2021,26(4)
Nicotinamide-N-methyltransferase (NNMT) is a cytosolic enzyme catalyzing the transfer of a methyl group from S-adenosyl-methionine (SAM) to nicotinamide (Nam). It is expressed in many tissues including the liver, adipose tissue, and skeletal muscle. Its expression in several cancer cell lines has been widely discussed in the literature, and recent work established a link between NNMT expression and metabolic diseases. Here we describe our approach to identify potent small molecule inhibitors of NNMT featuring different binding modes as elucidated by X-ray crystallographic studies. 相似文献
57.
Montasser Hijazi Esra Türkmen Prof. Dr. Joerg C. Tiller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(59):13367-13371
Controlling the activity of enzymes is an important feature for many processes in medicine, bioanalytics, and biotechnology. So far, it has not been possible to fully switch biocatalysts on and off by thermoresponsive enzyme inhibitors. Herein, we present poly(2-oxazoline)s with iminodiacetic acid end groups (POx-IDA) that are lower critical solution temperature (LCST) polymers and thus thermosensitive. They are capable of reversibly inhibiting the activity of horse radish peroxidase and laccase by more than 99 %. Increasing the temperature makes the POx-IDA precipitate, which leads to 100 % recovery of the enzyme activity. This switching cycle is fully reversible. The LCST of the POx-IDA can be tuned by varying the polymer composition to generate a wide range of switching windows. 相似文献
58.
The first azo dye that gels from its aqueous solution was synthesized and its moist hydrogel was investigated with electron microscopy and atomic force microscopy; the anionic azo dye in aqueous solution forms a hydrogel on cationic surfaces even at concentrations 50 times below the minimal gelation concentration. 相似文献
59.
Joerg Freitag You Yokoyama Hidetoshi Kuramochi Katsuya Kawamoto Kunio Nagahama Satoru Kato 《Fluid Phase Equilibria》2007
The solubilities of phenylalanine and tyrosine in supercritical carbon dioxide (SCCO2) were measured after derivatization as the N-acetyl amino acid ethyl ester, N-carbobenzoxy amino acid and N-acetyl amino acid. Using an SCCO2 flow system, a measuring method of the saturated solubilities of the derivatized amino acids was established in which the contact height of the extraction cell, i.e. a packed column, is increased till the concentration of a derivatized amino acid at the exit of the cell reaches a plateau. The solubilities of N-acetyl phenylalanine ethyl ester (APEE) exceeded 0.001 mole fraction, which is higher than those of caffeine produced in industrial SCCO2 processes. A possible way of separating the amino acid mixtures using polarity differences in different amino acid side chains was demonstrated using the solubility data of the N-acetyl-amino acid ethyl esters in SCCO2, as the solubilities of APEE are higher than those of N-acetyl tyrosine ethyl ester by two orders of magnitude. 相似文献
60.
Joerg Beythien 《Tetrahedron letters》2005,46(1):101-104
A novel linker strategy for the efficient synthesis of peptides C-terminally labelled with the EDANS fluorophore is described. Using this support, FRET peptide substrates bearing EDANS/Dabcyl fluorescent donor/acceptor groups can be readily prepared using standard Fmoc solid phase methods. 相似文献