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21.
The new composite material Textile Reinforced Concrete (TRC) is a promising development which may open up entirely new fields for the application of the construction material concrete. The possible more filigree structures with high quality surfaces make TRC an attractive choice for the architect and give the engineer more freedom in design. However, the use of TRC requires design rules which are currently being developed at RWTH Aachen University, Germany. In this article, recent experimental results as well as modeling techniques are described.  相似文献   
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M.E. Will 《低温学》2006,46(6):421-431
In our laboratory we work an a new type of pulse-tube refrigerator. A complete set of relations is derived for the operation of counterflow pulse-tube refrigerators. The input parameters depend on the working fluid, the geometries of the pulse tube and the counterflow heat exchanger, and the compressor characteristics. The calculated molar flow in the heat exchanger agree within 5% with the measured value. The calculated and experimental lowest temperature and the temperature difference between the hot and cold gas in the heat exchanger agree within 10%. This larger difference is caused by difference between the modelled and real heat exchanger.  相似文献   
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The inclusion of an expander with work recovery provides two advantages for transcritical CO2 refrigeration cycles: the COP is improved and the exhaust pressure of the main compressor is lowered. Several designs of expanders have been proposed for this application and some prototypes have been tested already. In our laboratory a three-stage expander has been developed, which replaces the throttle valve of the normal refrigeration cycle and expands into the two-phase region. For optimum integration into the overall system it is proposed to install a vapour-liquid separator between the second and third stage of expansion. The vapour is guided back to the third expander stage whereas the liquid is supplied to the cooling stations via thermostatic or electronic expansion valves.  相似文献   
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Megakaryocytes release submicron size microparticles (MkMPs) in circulation. We have shown that MkMPs target CD34+ hematopoietic stem/progenitor cells (HSPCs) to induce megakaryocytic differentiation, and that small RNAs in MkMPs play an important role in the development of this phenotype. Here, using single-molecule real-time (SMRT) RNA sequencing (RNAseq), we identify the synergetic effect of two microRNAs (miRs), miR-486-5p and miR-22-3p (highly enriched in MkMPs), in driving the Mk differentiation of HSPCs in the absence of thrombopoietin (TPO). Separately, our data suggest that the MkMP-induced Mk differentiation of HSPCs is enabled through JNK and PI3K/Akt/mTOR signaling. The interaction between the two signaling pathways is likely mediated by a direct target of miR-486-5p and a negative regulator of PI3K/Akt signaling, the phosphatase and tensin homologue (PTEN) protein. Our data provide a possible mechanistic explanation of the biological effect of MkMPs in inducing megakaryocytic differentiation of HSPCs, a phenotype of potential physiological significance in stress megakaryopoiesis.  相似文献   
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有效管理     
<正>当租赁公司要削减费用时,必然要面临"有效管理"的问题。在做下一次费用削减之前,要问一问自己是否每次都能做出正确的决定。WL联合公司的Will Leftwich报道。  相似文献   
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The physical nature of current location-tracked mobile culture can open up new sites to explore our relationship to place and question our cultural reliance upon it. Recent projects by London-based multidisciplinary design studio UniversalAssemblyUnit playfully offer a shared-ownership alternative to commercially driven centralised networks. The studio's cofounders Will Gowland and Samantha Lee here outline three such projects, involving a weather visualiser for Alaska, a laser communication network for Mexico City and a virtual replica of woodland for East Sussex.  相似文献   
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