| 1. |
- Abata, E., et al.
(författare)
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Study of energy response and resolution of the ATLAS barrel calorimeter to hadrons of energies from 20 to 350 GeV
- 2010
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 621:1-3, s. 134-150
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Tidskriftsartikel (refereegranskat)abstract
- A fully instrumented slice of the ATLAS detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. In this paper, the results of the measurements of the response of the barrel calorimeter to hadrons with energies in the range 20-350 GeV and beam impact points and angles corresponding to pseudo-rapidity values in the range 0.2-0.65 are reported. The results are compared to the predictions of a simulation program using the Geant 4 toolkit. (C) 2010 Published by Elsevier B.V.
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| 2. |
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| 3. |
- Meng, X., et al.
(författare)
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Pulse width modulation for multi-agent systems
- 2016
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Ingår i: Automatica. - : Elsevier. - 0005-1098 .- 1873-2836. ; 70, s. 173-178
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Tidskriftsartikel (refereegranskat)abstract
- This paper studies the consensus problem for multi-agent systems. A distributed consensus algorithm is developed by constructing homogeneous pulse width modulators for agents in the network. In particular, a certain percentage of the sampling period named duty cycle is modulated according to some state difference with respect to the neighbors at each sampling instant. During each duty cycle, the amplitude of the pulse is fixed. The proposed pulse width modulation scheme enables all agents to sample asynchronously with arbitrarily large sampling periods. It provides an alternative digital implementation strategy for multi-agent systems. We show that consensus is achieved asymptotically under the proposed scheme. The results are compared with the self-triggered ternary controller.
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| 4. |
- Meng, X. X. Y., et al.
(författare)
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Humidity-Dependent Phase State of Gasoline Vehicle Emission-Related Aerosols
- 2021
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:2, s. 832-841
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Tidskriftsartikel (refereegranskat)abstract
- The phase states of primarily emitted and secondarily formed aerosols from gasoline vehicle exhausts were investigated by quantifying the particle rebound fraction (f). The rebound behaviors of gasoline vehicle emission-related aerosols varied with engines, fuel types, and photochemical aging time, showing distinguished differences from biogenic secondary organic aerosols. The nonliquid-to-liquid phase transition of primary aerosols emitted from port fuel injection (PFI) and gasoline direct injection (GDI) vehicles started at a relative humidity (RH) = 50 and 60%, and liquefaction was accomplished at 60 and 70%, respectively. The RH at which f declined to 0.5 decreased from 70 to 65% for the PFI case with 92# fuel, corresponding to the photochemical aging time from 0.37 to 4.62 days. For the GDI case, such RH enhanced from 60 to 65%. Our results can be used to imply the phase state of traffic-related aerosols and further understand their roles in urban atmospheric chemistry. Taking Beijing, China, as an example, traffic-related aerosols were mainly nonliquid during winter with the majority ambient RH below 50%, whereas they were mostly liquid during the morning rush hour of summer, and traffic-related secondary aerosols fluctuated between nonliquid and liquid during the daytime and tended to be liquid at night with increased ambient RH.
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| 5. |
- Liang, X., et al.
(författare)
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Numerical investigations on outdoor thermal comfort for built environment : Case study of a Northwest campus in China
- 2019
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Ingår i: Energy Procedia. - : Elsevier Ltd. - 1876-6102. ; , s. 6557-6563, s. 6557-6563
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Konferensbidrag (refereegranskat)abstract
- Outdoor thermal comfort has been receiving more and more attentions due to the increased demand of outdoor activities during last decades. People require good thermal comfort when they are exposed to the outdoor thermal environment. However, the natural environment is severely suffering from the pollution of air, water as well as the extremely hot weather. Therefore, construction of ecological living environment is of great importance. To evaluate and improve the built environment, a campus area located in Northwest China was selected. Numerical simulations based on the software ENVI-met V4.0 were conducted and the effect of growing plants upon the outdoor thermal comfort was analyzed. Numerical results were compared using different thermal Indexes: Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI). Results demonstrated that UTCI gave a lower prediction than that of PET and was more suitable for evaluating the outdoor thermal comfort. Growing trees can significantly reduce the uncomfortable hours during hot summer but the improvement will reach the limitation after growing amount of trees.
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| 6. |
- Meng, B., et al.
(författare)
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Research Progress on the Architecture and Key Technologies of Machine Tool Intelligent Control System
- 2021
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Ingår i: Jixie Gongcheng Xuebao/Journal of Mechanical Engineering. - : Chinese Mechanical Engineering Society. - 0577-6686. ; 57:9, s. 147-166
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Tidskriftsartikel (refereegranskat)abstract
- Machine tool intelligent control system, as an integral part of future intelligent machine tools, plays a significant role in improving core competencies of manufacture. Compared with traditional CNC system, the intelligent one has the advantage of higher efficiency and more stable manufacturing quality. It's able to make intelligent decisions and substitute experiences of human operators. Considering that there are few reviews on intelligent control system of machine tools, the framework and architecture of the machine tool intelligent control system is proposed by analyzing features from four stages of historical development of the machine tool control system. From the perspective of advanced technology, the related key technologies and engineering applications are elaborated, such as artificial intelligence, digital twins and cloud services. At last, after analyzing several major challenges of intelligent machine tools and their countermeasures, the future development trend of machine tool intelligent control system is forecasted.
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| 7. |
- Meng, Z., et al.
(författare)
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Multiagent systems with compasses
- 2015
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Ingår i: SIAM Journal of Control and Optimization. - : Society for Industrial & Applied Mathematics (SIAM). - 0363-0129 .- 1095-7138. ; 53:5, s. 3057-3080
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates agreement protocols over cooperative and cooperativeantagonistic multiagent networks with coupled continuous-time nonlinear dynamics. To guarantee convergence for such systems, it is common in the literature to assume that the vector field of each agent is pointing inside the convex hull formed by the states of the agent and its neighbors, given that the relative states between each agent and its neighbors are available. This convexity condition is relaxed in this paper, as we show that it is enough that the vector field belongs to a strict tangent cone based on a local supporting hyperrectangle. The new condition has the natural physical interpretation of requiring shared reference directions in addition to the available local relative states. Such shared reference directions can be further interpreted as if each agent holds a magnetic compass indicating the orientations of a global frame. It is proved that the cooperative multiagent system achieves exponential state agreement if and only if the time-varying interaction graph is uniformly jointly quasi-strongly connected. Cooperative-antagonistic multiagent systems are also considered. For these systems, the relation has a negative sign for arcs corresponding to antagonistic interactions. State agreement may not be achieved, but instead it is shown that all the agents' states asymptotically converge, and their limits agree componentwise in absolute values if and in general only if the time-varying interaction graph is uniformly jointly strongly connected.
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| 8. |
- Wang, Z., et al.
(författare)
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Intelligent Monitoring and Control Technology of Cutting Chatter
- 2020
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Ingår i: Jixie Gongcheng Xuebao/Journal of Mechanical Engineering. - : Chinese Mechanical Engineering Society. - 0577-6686. ; 56:24, s. 1-23
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Tidskriftsartikel (refereegranskat)abstract
- Intelligent monitoring and control technology of cutting chatter is an indispensable part of intelligent machine tools and an important development direction of intelligent machining. It is of great significance to improve machining accuracy and efficiency of parts and increase the operation performance of enterprises. Based on the main line of sensor selection, feature extraction, chatter recognition and chatter suppression, the research progress of intelligent monitoring and control of chatter in cutting process is systematically reviewed. The selection of chatter signal and the methods of feature extraction in time domain, frequency domain, time-frequency domain and feature adaptive intelligent extraction are analyzed. The application of neural network, support vector machine, hidden Markov model, hybrid model and online intelligent evolution mode in chatter recognition are analyzed. The intelligent control method of chatter based on spindle speed variation are emphatically analyzed. On this basis, the research difficulties are analyzed and the existing problems are summarized in intelligent monitoring and control technology of cutting chatter. Finally, the development trend of intelligent monitoring and control technology of cutting chatter is forecasted.
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| 9. |
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| 10. |
- Grieser, M., et al.
(författare)
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Storage ring at HIE-ISOLDE
- 2012
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Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 207:1, s. 1-117
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Tidskriftsartikel (refereegranskat)abstract
- We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
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