Atactic amorphous poly(propylene) of various molecular weights has been modified with high energy electrons over an irradiation dose range of 0–200 kGy. Tri‐ and tetrafunctional monomers in varied concentrations have been used as crosslinking additives. A correlation between the original molecular weight and crosslinking behavior of the polymer was observed. A higher gel content is obtained with the tetrafunctional acrylate as compared to that with the trifunctional one, under the same treatment conditions. Electron irradiation treatment at elevated temperature gives rise to an increased gel content over that at room temperature. Similarly, the mechanical properties also enhance with gel content. Moreover, the stress‐strain behavior of the electron modified systems indicates a more pronounced elastomeric nature.
NFB plays an important role in mediating the gene expressionof numerous cellular processes such as growth, development,the inflammatory response and virus proliferation. The p50/p65heterodimer is the most abundant form of the NFB dimers andplays a more elaborate role in gene regulation. Biochemicalresearch on p50/p65 NFB has not benefited however from the availabilityof easily purified recombinant protein. We report two methodsfor the large scale expression and purification of recombinantNFB p50/p65 heterodimer. The first utilizes a bacterial doubleexpression vector which contains two ribosomal binding sitesto facilitate the coexpression of the polypeptides in the p50/p65NFB heterodimer. The second method uses a mixed protein refoldingstrategy. Both methods yield crystallizable protein. Electrophoreticmobility shift assays confirm that the DNA binding affinityis independent of the method used to purify the protein. Thesemethods will facilitate the numerous studies on various NFB/Relfamily members. 相似文献
Active noise reduction, structural health monitoring and energy harvesting are possible applications of active structure components. An integration of piezoceramic modules into casted Al-structures can be defined as a long term goal to achieve high functional integration and thus to address lightweight construction. Since the liquidus temperature of standard electronic solder is not sufficient to withstand the thermal loads during Al die casting processes, a suitable wire bonding process is an enabling technology to generate active Al structures. In the scope of this work, a laser based drop on demand joining process is introduced. The process consists of four main steps. First a spherical CuSn12 braze preform of 600 µm diameter with a liquidus temperature of 1233 K is inserted into a ceramic capillary and being molten by a laser pulse. The droplet is subsequently ejected by gas overpressure and impinges on the joining area, consisting of the electrode structure of the piezo element and the Cu wire, where it forms a firm joint of the Cu wire and the electrode structure. In order to evaluate time–temperature profiles of the capillary during melting and detachment of the braze preform a simulation model was set up, indicating heating and cooling rates of 22,100 K/s. Further, the impact of the capillary geometry on the velocity fields of a passing medium was evaluated. By changing the capillary geometry, the gas flow velocity could be reduced by about 10% according to the simulation model, which resulted in a reduction of droplet height deviation of 7.5% and a reduction of the droplet diameter deviation of 32.2% in the experiment. 相似文献
Forschung im Ingenieurwesen - Der Einsatz von Getrieben in elektrifizierten Antriebssträngen und Flugzeugturbinen führt zu höheren Betriebsdrehzahlen und einer höheren Anzahl... 相似文献
Emergent behaviors occur when simple interactions between a system's constituent elements produce properties that the individual elements do not exhibit in isolation. This article reports tunable emergent behaviors observed in domain wall (DW) populations of arrays of interconnected magnetic ring-shaped nanowires under an applied rotating magnetic field. DWs interact stochastically at ring junctions to create mechanisms of DW population loss and gain. These combine to give a dynamic, field-dependent equilibrium DW population that is a robust and emergent property of the array, despite highly varied local magnetic configurations. The magnetic ring arrays’ properties (e.g., non-linear behavior, “fading memory” to changes in field, fabrication repeatability, and scalability) suggest they are an interesting candidate system for realizing reservoir computing (RC), a form of neuromorphic computing, in hardware. By way of example, simulations of ring arrays performing RC approaches 100% success in classifying spoken digits for single speakers. 相似文献
Bombyx mori silks possess great potential in textile industries due to the large-scale green production. However, the demand for silks with functional as well as mechanical properties are continuously rising due to the emergence of other functional textiles. It remains a great challenge to functionalize natural silk and simultaneously improve its mechanical properties. Inspired by the relationship between natural core–sheath structure and mechanical properties of cocoon silk, the application of a thin reduced graphene oxide (rGO) layer coated B. mori silk (GS) is shown via hydrogen interfacial interaction. The resultant rGO-coated silk exhibits a remarkable tensile strength of 1137.7 MPa and toughness of 304.5 MJ m−3, which are 1.9 and 2.6 times higher than that of pure B. mori silk, respectively. Moreover, the GS shows a high electrical conductivity of 0.37 S m−1 with great thermal and deformation sensitivity. The bioinspired approach provides a universal and facile strategy for functionalizing natural fibers by applying rGO nanosheets surface coating. 相似文献
