4,390 research outputs found
Study of hot processing map of AISI 1035 steel under high temperature
In this study, AISI 1035 steel was selected as the research object, and a single-pass thermal compression simulation experiment was carried out. Based on the true stress-strain curve obtained from the experiment, the dynamic DMM thermal processing map theory was used to draw the material under different thermal deformation conditions. and the rheological instability map based on the Prasad instability criterion, and the thermal processing map is used to predict the suitable processing interval and rheological instability interval for the thermal deformation process of the material under different process conditions. So as to provide theoretical support for the optimization of the material processing technology
Numerical simulation of the blasting vibration response of shallow buried tunnel in complex urban environment
Base on the phase I project of Nanjing metro line IV, the blasting vibration response of shallow buried tunnel in complex urban environment was studied with ANSYS/LS-DYNA, the real load change was simulated with the loading way of measured stress curve, and there was a consistent between numerical simulation results and the measured data. The numerical results indicated that the velocity distribution in different directions were close in the close area (0-2Â m); the vertical seismic wave attenuated at the fastest speed in the transferring process, and the radial seismic wave attenuated the fastest in the excavation direction ; in the distance from 2Â m to 5Â m, the tangential and radial vibration of the initiating side were both obviously larger than the other side of the core tube, which was still more violent than the vertical vibration, and the difference decreases with the distance increases. In the surrounding rocks , the radial vibration velocity was the biggest and attenuated at the fastest speed, which was close to linear attenuation ;the tangential vibration velocity is the smallest with the a relatively gentler damping, the vertical vibration attenuated until 8Â m and then increased gradually and the resultant velocity obeyed the exponential damping law
Metagenomic Insights Into the Cycling of Dimethylsulfoniopropionate and Related Molecules in the Eastern China Marginal Seas
The microbial cycling of dimethylsulfoniopropionate (DMSP) and its gaseous catabolites dimethylsulfide (DMS) and methanethiol (MeSH) are important processes in the global sulfur cycle, marine microbial food webs, signaling pathways, atmospheric chemistry, and potentially climate regulation. Many functional genes have been identified and used to study the genetic potential of microbes to produce and catabolize these organosulfur compounds in different marine environments. Here, we sampled seawater, marine sediment and hydrothermal sediment, and polymetallic sulfide in the eastern Chinese marginal seas and analyzed their microbial communities for the genetic potential to cycle DMSP, DMS, and MeSH using metagenomics. DMSP was abundant in all sediment samples, but was fivefold less prominent in those from hydrothermal samples. Indeed, Yellow Sea (YS) sediment samples had DMSP concentrations two orders of magnitude higher than in surface water samples. Bacterial genetic potential to synthesize DMSP (mainly in Rhodobacteraceae bacteria) was far higher than for phytoplankton in all samples, but particularly in the sediment where no algal DMSP synthesis genes were detected. Thus, we propose bacteria as important DMSP producers in these marine sediments. DMSP catabolic pathways mediated by the DMSP lyase DddP (prominent in Pseudomonas and Mesorhizobium bacteria) and DMSP demethylase DmdA enzymes (prominent in Rhodobacteraceae bacteria) and MddA-mediated MeSH S-methylation were very abundant in Bohai Sea and Yellow Sea sediments (BYSS) samples. In contrast, the genetic potential for DMSP degradation was very low in the hydrothermal sediment samples—dddP was the only catabolic gene detected and in only one sample. However, the potential for DMS production from MeSH (mddA) and DMS oxidation (dmoA and ddhA) was relatively abundant. This metagenomics study does not provide conclusive evidence for DMSP cycling; however, it does highlight the potential importance of bacteria in the synthesis and catabolism of DMSP and related compounds in diverse sediment environments
Monitoring Avian Influenza Viruses from Chicken Carcasses Sold at Markets, China, 2016
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Scalable Method for Eliminating Residual Interaction between Superconducting Qubits
Unwanted interaction is a quantum-mechanical crosstalk phenomenon which
correlates qubit dynamics and is ubiquitous in superconducting qubit systems.
It adversely affects the quality of quantum operations and can be detrimental
in scalable quantum information processing. Here we propose and experimentally
demonstrate a practically extensible approach for complete cancellation of
residual interaction between fixed-frequency transmon qubits, which are
known for long coherence and simple control. We apply to the intermediate
coupler that connects the qubits a weak microwave drive at a properly chosen
frequency in order to noninvasively induce an ac Stark shift for
cancellation. We verify the cancellation performance by measuring vanishing
two-qubit entangling phases and correlations. In addition, we implement a
randomized benchmarking experiment to extract the idling gate fidelity which
shows good agreement with the coherence limit, demonstrating the effectiveness
of cancellation. Our method allows independent addressability of each
qubit-qubit connection, and is applicable to both nontunable and tunable
couplers, promising better compatibility with future large-scale quantum
processors.Comment: Main text: 6 pages, 4 figures; Supplement: 7 pages, 6 figure
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